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Pampalone G, Chiasserini D, Pierigè F, Camaioni E, Orvietani PL, Bregalda A, Menotta M, Bellezza I, Rossi L, Cellini B, Magnani M. Biochemical Studies on Human Ornithine Aminotransferase Support a Cell-Based Enzyme Replacement Therapy in the Gyrate Atrophy of the Choroid and Retina. Int J Mol Sci 2024; 25:7931. [PMID: 39063173 PMCID: PMC11277095 DOI: 10.3390/ijms25147931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2024] [Revised: 07/12/2024] [Accepted: 07/17/2024] [Indexed: 07/28/2024] Open
Abstract
The gyrate atrophy of the choroid and retina (GACR) is a rare genetic disease for which no definitive cure is available. GACR is due to the deficit of ornithine aminotransferase (hOAT), a pyridoxal 5'-phosphate-dependent enzyme responsible for ornithine catabolism. The hallmark of the disease is plasmatic ornithine accumulation, which damages retinal epithelium leading to progressive vision loss and blindness within the fifth decade. Here, we characterized the biochemical properties of tetrameric and dimeric hOAT and evaluated hOAT loaded in red blood cells (RBCs) as a possible enzyme replacement therapy (ERT) for GACR. Our results show that (i) hOAT has a relatively wide specificity for amino acceptors, with pyruvate being the most suitable candidate for ornithine catabolism within RBCs; (ii) both the tetrameric and dimeric enzyme can be loaded in RBC retaining their activity; and (iii) hOAT displays reduced stability in plasma, but is partly protected from inactivation upon incubation in a mixture mimicking the intracellular erythrocyte environment. Preliminary ex vivo experiments indicate that hOAT-loaded RBCs are able to metabolize extracellular ornithine at a concentration mimicking that found in patients, both in buffer and, although with lower efficiency, in plasma. Overall, our data provide a proof of concept that an RBC-mediated ERT is feasible and can be exploited as a new therapeutic approach in GACR.
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Affiliation(s)
- Gioena Pampalone
- Department of Medicine and Surgery, University of Perugia, P.le L. Severi 1, 06132 Perugia, Italy; (G.P.); (D.C.); (P.L.O.); (I.B.)
| | - Davide Chiasserini
- Department of Medicine and Surgery, University of Perugia, P.le L. Severi 1, 06132 Perugia, Italy; (G.P.); (D.C.); (P.L.O.); (I.B.)
| | - Francesca Pierigè
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, 61029 Urbino, Italy; (F.P.); (A.B.); (M.M.); (M.M.)
| | - Emidio Camaioni
- Department of Pharmaceutical Sciences, University of Perugia, Via del Liceo 1, 06122 Perugia, Italy;
| | - Pier Luigi Orvietani
- Department of Medicine and Surgery, University of Perugia, P.le L. Severi 1, 06132 Perugia, Italy; (G.P.); (D.C.); (P.L.O.); (I.B.)
| | - Alessandro Bregalda
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, 61029 Urbino, Italy; (F.P.); (A.B.); (M.M.); (M.M.)
| | - Michele Menotta
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, 61029 Urbino, Italy; (F.P.); (A.B.); (M.M.); (M.M.)
| | - Ilaria Bellezza
- Department of Medicine and Surgery, University of Perugia, P.le L. Severi 1, 06132 Perugia, Italy; (G.P.); (D.C.); (P.L.O.); (I.B.)
| | - Luigia Rossi
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, 61029 Urbino, Italy; (F.P.); (A.B.); (M.M.); (M.M.)
| | - Barbara Cellini
- Department of Medicine and Surgery, University of Perugia, P.le L. Severi 1, 06132 Perugia, Italy; (G.P.); (D.C.); (P.L.O.); (I.B.)
| | - Mauro Magnani
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, 61029 Urbino, Italy; (F.P.); (A.B.); (M.M.); (M.M.)
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Abo Qoura L, Balakin KV, Hoffman RM, Pokrovsky VS. The potential of methioninase for cancer treatment. Biochim Biophys Acta Rev Cancer 2024; 1879:189122. [PMID: 38796027 DOI: 10.1016/j.bbcan.2024.189122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 05/07/2024] [Accepted: 05/21/2024] [Indexed: 05/28/2024]
Abstract
Cancer cells are addicted to L-methionine (L-Met) and have a much greater requirement for L-Met than normal cells due to excess transmethylation, termed the Hoffman effect. By targeting this vulnerability through dietary restriction of L-Met, researchers have been able to achieve promising results in inhibiting tumor growth and eradicating cancer cells. Methioninase (EC 4.4.1.11; METase) catalyzes the transformation of L-Met into α-ketobutyrate, ammonia, and methanethiol. The use of METase was initially limited due to its poor stability in vivo, high immunogenicity, and enzyme-induced inactivating antibodies. These issues could be partially resolved by PEGylation, encapsulation in erythrocytes, and various site-directed mutagenesis. The big breakthrough came when it was discovered that METase is effectively administered orally. The enzyme L-asparaginase is approved by the FDA for treatment of acute lymphoblastic leukemia. METase has more potential as a therapeutic since addiction to L-Met is a general and fundamental hallmark of cancer.
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Affiliation(s)
- Louay Abo Qoura
- Research Institute of Molecular and Cellular Medicine, People's Friendship University of Russia (RUDN University), 117198 Moscow, Russia; N.N. Blokhin National Medical Research Center of Oncology of Ministry of Health of Russian Federation, 115478 Moscow, Russia
| | | | - Robert M Hoffman
- AntiCancer Inc., San Diego, CA 92111, USA; Department of Surgery, University of California, San Diego, La Jolla, CA 92037-7400, USA
| | - Vadim S Pokrovsky
- Research Institute of Molecular and Cellular Medicine, People's Friendship University of Russia (RUDN University), 117198 Moscow, Russia; N.N. Blokhin National Medical Research Center of Oncology of Ministry of Health of Russian Federation, 115478 Moscow, Russia.
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Bianchi M, Rossi L, Pierigè F, Biagiotti S, Bregalda A, Tasini F, Magnani M. Preclinical and clinical developments in enzyme-loaded red blood cells: an update. Expert Opin Drug Deliv 2023; 20:921-935. [PMID: 37249524 DOI: 10.1080/17425247.2023.2219890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 05/26/2023] [Indexed: 05/31/2023]
Abstract
INTRODUCTION We have previously described the preclinical developments in enzyme-loaded red blood cells to be used in the treatment of several rare diseases, as well as in chronic conditions. AREA COVERED Since our previous publication we have seen further progress in the previously discussed approaches and, interestingly enough, in additional new studies that further strengthen the idea that red blood cell-based therapeutics may have unique advantages over conventional enzyme replacement therapies in terms of efficacy and safety. Here we highlight these investigations and compare, when possible, the reported results versus the current therapeutic approaches. EXPERT OPINION The continuous increase in the number of new potential applications and the progress from the encapsulation of a single enzyme to the engineering of an entire metabolic pathway open the field to unexpected developments and confirm the role of red blood cells as cellular bioreactors that can be conveniently manipulated to acquire useful therapeutic metabolic abilities. Positioning of these new approaches versus newly approved drugs is essential for the successful transition of this technology from the preclinical to the clinical stage and hopefully to final approval.
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Affiliation(s)
- Marzia Bianchi
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Luigia Rossi
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
- EryDel SpA, Bresso, MI, Italy
| | - Francesca Pierigè
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Sara Biagiotti
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Alessandro Bregalda
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Filippo Tasini
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Mauro Magnani
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
- EryDel SpA, Bresso, MI, Italy
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Shichinohe N, Kobayashi D, Izumi A, Hatanaka K, Fujita R, Kinoshita T, Inoue N, Hamaue N, Wada K, Murakami Y. Sequential hydrolysis of FAD by ecto-5' nucleotidase CD73 and alkaline phosphatase is required for uptake of vitamin B 2 into cells. J Biol Chem 2022; 298:102640. [PMID: 36309091 PMCID: PMC9694112 DOI: 10.1016/j.jbc.2022.102640] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 10/18/2022] [Accepted: 10/20/2022] [Indexed: 11/24/2022] Open
Abstract
Extracellular hydrolysis of flavin-adenine dinucleotide (FAD) and flavin mononucleotide (FMN) to riboflavin is thought to be important for cellular uptake of vitamin B2 because FAD and FMN are hydrophilic and do not pass the plasma membrane. However, it is not clear whether FAD and FMN are hydrolyzed by cell surface enzymes for vitamin B2 uptake. Here, we show that in human cells, FAD, a major form of vitamin B2 in plasma, is hydrolyzed by CD73 (also called ecto-5' nucleotidase) to FMN. Then, FMN is hydrolyzed by alkaline phosphatase to riboflavin, which is efficiently imported into cells. We determined that this two-step hydrolysis process is impaired on the surface of glycosylphosphatidylinositol (GPI)-deficient cells due to the lack of these GPI-anchored enzymes. During culture of GPI-deficient cells with FAD or FMN, we found that hydrolysis of these forms of vitamin B2 was impaired, and intracellular levels of vitamin B2 were significantly decreased compared with those in GPI-restored cells, leading to decreased formation of vitamin B2-dependent pyridoxal 5'-phosphate and mitochondrial dysfunction. Collectively, these results suggest that inefficient uptake of vitamin B2 might account for mitochondrial dysfunction seen in some cases of inherited GPI deficiency.
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Affiliation(s)
- Natsuki Shichinohe
- Department of Food and Chemical Toxicology, School of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido, Japan
| | - Daisuke Kobayashi
- Department of Food and Chemical Toxicology, School of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido, Japan,For correspondence: Yoshiko Murakami; Daisuke Kobayashi
| | - Ayaka Izumi
- Department of Food and Chemical Toxicology, School of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido, Japan
| | - Kazuya Hatanaka
- Department of Food and Chemical Toxicology, School of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido, Japan
| | - Rio Fujita
- Department of Food and Chemical Toxicology, School of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido, Japan
| | - Taroh Kinoshita
- Laboratory of Immunoglycobiology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan,WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan,Center for Infectious Disease Education and Research, Osaka University, Suita, Osaka, Japan
| | - Norimitsu Inoue
- Department of Molecular Genetics, Wakayama Medical University, Wakayama, Wakayama, Japan
| | - Naoya Hamaue
- Department of Food and Chemical Toxicology, School of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido, Japan
| | - Keiji Wada
- Department of Food and Chemical Toxicology, School of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido, Japan
| | - Yoshiko Murakami
- Laboratory of Immunoglycobiology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan,WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan,For correspondence: Yoshiko Murakami; Daisuke Kobayashi
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Rossi L, Pierigè F, Bregalda A, Magnani M. Preclinical developments of enzyme-loaded red blood cells. Expert Opin Drug Deliv 2020; 18:43-54. [PMID: 32924643 DOI: 10.1080/17425247.2020.1822320] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
INTRODUCTION Therapeutic enzymes are currently used in the treatment of several diseases. In most cases, the benefits are limited due to poor in vivo stability, immunogenicity, and drug-induced inactivating antibodies. A partial solution to the problem is obtained by masking the therapeutic protein by chemical modifications. Unfortunately, this is not a satisfactory solution because frequent adverse events, including anaphylaxis, can arise. AREA COVERED Among the delivery systems, we focused on red blood cells for the delivery of therapeutic enzymes. Erythrocytes possess a long circulation time, a reduced immunogenicity, there is no need of chemical modifications and the encapsulated enzyme remains active because it is protected by the cell membrane. Here we discuss some representative applications of the preclinical developments of the field. Some of these are currently in clinic, others are approaching the clinic and others are illustrative of the development process. The selected examples are not always the most recent, but they are the most useful for a comparative approach. EXPERT OPINION The results discussed confirm the central role that red blood cells can play in the treatment of several conditions and suggest the benefit in using a natural cellular carrier in terms of pharmacokinetic, biodistribution, safety, and efficacy.
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Affiliation(s)
- Luigia Rossi
- Department of Biomolecular Sciences, University of Urbino , Urbino, Italy.,EryDel SpA , Bresso, Italy
| | - Francesca Pierigè
- Department of Biomolecular Sciences, University of Urbino , Urbino, Italy
| | | | - Mauro Magnani
- Department of Biomolecular Sciences, University of Urbino , Urbino, Italy.,EryDel SpA , Bresso, Italy
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Nimker S, Sharma K, Saraswathy R, Chandna S. Delineating the Effects of Ionizing Radiation on Erythropoietic Lineage-Implications for Radiation Biodosimetry. HEALTH PHYSICS 2019; 116:677-693. [PMID: 30720544 DOI: 10.1097/hp.0000000000000975] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The overall lethality/morbidity of ionizing radiation exposure involves multiple forms of inhibitory or cytotoxic effects that may manifest in different tissues with a varying dose and time response. One of the major systemic effects leading to lethality of radiation includes its suppressive effect on hematopoiesis, which could be observed even at doses as low as 1-2 Gy, whereas effects on gastrointestinal and nervous systems appear at relatively higher doses in the same order. This article reviews the effects of radiation on the three distinct stages of erythropoiesis-formation of erythroid progenitor cells, differentiation of erythroid precursor cells, and terminal maturation. During these stepwise developmental processes, erythroid progenitor cells undergo rapid expansion to form terminally differentiated red blood cells that are continuously replenished from bone marrow into the circulating peripheral blood stream. Cellular radiation response depends upon many factors such as cell lineage, rate of proliferation, and differentiation status. Therefore, we discuss radiation-induced alterations during the progenitor, precursor, and terminal maturation stages and the implications thereof. Since biomarkers of ionizing radiation exposure in human populations are of great interest for assessing normal tissue injury as well as for biodosimetry in the event of accidental or incidental radiation exposures, we also highlight blood-based biomarkers that have potential utility for medical management.
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Affiliation(s)
- Shwetanjali Nimker
- Division of Natural Radiation Response Mechanisms, Institute of Nuclear Medicine and Allied Sciences, Timarpur, Delhi, India
- School of Biosciences and Technology, Vellore Institiute of Technology, Vellore, Tamil Nadu, India
| | - Kanupriya Sharma
- Division of Natural Radiation Response Mechanisms, Institute of Nuclear Medicine and Allied Sciences, Timarpur, Delhi, India
| | - Radha Saraswathy
- School of Biosciences and Technology, Vellore Institiute of Technology, Vellore, Tamil Nadu, India
| | - Sudhir Chandna
- Division of Natural Radiation Response Mechanisms, Institute of Nuclear Medicine and Allied Sciences, Timarpur, Delhi, India
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Machover D, Rossi L, Hamelin J, Desterke C, Goldschmidt E, Chadefaux-Vekemans B, Bonnarme P, Briozzo P, Kopečný D, Pierigè F, Magnani M, Mollicone R, Haghighi-Rad F, Gaston-Mathé Y, Dairou J, Boucheix C, Saffroy R. Effects in Cancer Cells of the Recombinant l-Methionine Gamma-Lyase fromBrevibacterium aurantiacum.Encapsulation in Human Erythrocytes for Sustained l-Methionine Elimination. J Pharmacol Exp Ther 2019; 369:489-502. [DOI: 10.1124/jpet.119.256537] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Accepted: 04/01/2019] [Indexed: 01/20/2023] Open
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Gay F, Aguera K, Sénéchal K, Tainturier A, Berlier W, Maucort-Boulch D, Honnorat J, Horand F, Godfrin Y, Bourgeaux V. Methionine tumor starvation by erythrocyte-encapsulated methionine gamma-lyase activity controlled with per os vitamin B6. Cancer Med 2017; 6:1437-1452. [PMID: 28544589 PMCID: PMC5463067 DOI: 10.1002/cam4.1086] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 03/17/2017] [Accepted: 03/26/2017] [Indexed: 12/27/2022] Open
Abstract
Erymet is a new therapy resulting from the encapsulation of a methionine gamma-lyase (MGL; EC number 4.4.1.11) in red blood cells (RBC). The aim of this study was to evaluate erymet potential efficacy in methionine (Met)-dependent cancers. We produced a highly purified MGL using a cGMP process, determined the pharmacokinetics/pharmacodynamics (PK/PD) properties of erymet in mice, and assessed its efficacy on tumor growth prevention. Cytotoxicity of purified MGL was tested in six cancer cell lines. CD1 mice were injected with single erymet product supplemented or not with vitamin B6 vitamer pyridoxine (PN; a precursor of PLP cofactor). NMRI nude mice were xenografted in the flank with U-87 MG-luc2 glioblastoma cells for tumor growth study following five intravenous (IV) injections of erymet with daily PN oral administration. Endpoints included efficacy and event-free survival (EFS). Finally, a repeated dose toxicity study of erymet combined with PN cofactor was conducted in CD1 mice. Recombinant MGL was cytotoxic on 4/6 cell lines tested. MGL half-life was increased from <24 h to 9-12 days when encapsulated in RBC. Conversion of PN into PLP by RBC was demonstrated. Combined erymet + PN treatment led to a sustained Met depletion in plasma for several days with a 85% reduction of tumor volume after 45 days following cells implantation, and a significant EFS prolongation for treated mice. Repeated injections in mice exhibited a very good tolerability with only minor impact on clinical state (piloerection, lean aspect) and a slight decrease in hemoglobin and triglyceride concentrations. This study demonstrated that encapsulation of methioninase inside erythrocyte greatly enhanced pharmacokinetics properties of the enzyme and is efficacy against tumor growth. The perspective on these results is the clinical evaluation of the erymet product in patients with Met starvation-sensitive tumors.
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Affiliation(s)
| | | | | | | | | | - Delphine Maucort-Boulch
- Service de Biostatistique, Hospices Civils de Lyon, Lyon, France.,Université Claude Bernard Lyon 1, Villeurbanne, France.,CNRS UMR 5558, Laboratoire de Biométrie et Biologie Evolutive, Equipe Biostatistique-Santé, Villeurbanne, France
| | - Jérôme Honnorat
- Université Claude Bernard Lyon 1, Villeurbanne, France.,Service de Neuro-oncologie, Hôpital neurologique, Hospices Civils de Lyon, Lyon, France.,Institut NeuroMyoGene INSERM U1217/CNRS UMR 5310, Lyon, France
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Midttun Ø, Hustad S, Schneede J, Vollset SE, Ueland PM. Plasma vitamin B-6 forms and their relation to transsulfuration metabolites in a large, population-based study. Am J Clin Nutr 2007; 86:131-8. [PMID: 17616772 DOI: 10.1093/ajcn/86.1.131] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Vitamin B-6 exists in different forms; one of those forms, pyridoxal 5'-phosphate (PLP), serves a cofactor in many enzyme reactions, including the transsulfuration pathway, in which homocysteine is converted to cystathionine and then to cysteine. Data on the relations between indexes of vitamin B-6 status and transsulfuration metabolites in plasma are sparse and conflicting. OBJECTIVE We investigated the distribution and associations of various vitamin B-6 species in plasma and their relation to plasma concentrations of transsulfuration metabolites. DESIGN Nonfasting blood samples from 10 601 healthy subjects with a mean age of 56.4 y were analyzed for all known vitamin B-6 vitamers, folate, cobalamin, riboflavin, total homocysteine, cystathionine, total cysteine, methionine, and creatinine. All subjects were genotyped for the methylenetetrahydrofolate reductase (MTHFR) 677C-->T polymorphism. RESULTS Plasma concentrations of the main vitamin B-6 vitamers--PLP, pyridoxal, and 4-pyridoxic acid--were strongly correlated. Among the vitamin B-6 vitamers, PLP showed the strongest and most consistent inverse relation to total homocysteine and cystathionine, but the dose response was different for the 2 metabolites. The PLP-total homocysteine relation was significant only in the lowest quartile of the vitamin B-6 distribution and was strongest in subjects with the MTHFR 677TT genotype, whereas cystathionine showed a graded response throughout the range of vitamin B-6 vitamer concentrations, and the effect was not modified by the MTHFR 677C-->T genotype. CONCLUSION This large population-based study provided precise estimates of the relation between plasma concentrations of vitamin B-6 forms and transsulfuration metabolites as modified by the MTHFR 677C-->T genotype.
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Oshiro M, Nonoyama K, Oliveira RAG, Barretto OCDO. Red cell aspartate aminotransferase saturation with oral pyridoxine intake. SAO PAULO MED J 2005; 123:54-7. [PMID: 15947830 DOI: 10.1590/s1516-31802005000200004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
CONTEXT AND OBJECTIVE The coenzyme of aspartate aminotransferase is pyridoxal phosphate, generated from fresh vegetables containing pyridoxine. Vitamin B6-responsive sideroblastic anemia, myelofibrosis and Peyronies syndrome respond to high pyridoxine doses. The objective was to investigate the oral pyridoxine oral dose that would lead to maximized pyridoxal phosphate saturation of red cell aspartate aminotransferase. DESIGN AND SETTING Controlled trial, in Hematology Division of Instituto Adolfo Lutz. METHODS Red cell aspartate aminotransferase activity was assayed (before and after) in normal volunteers who were given oral pyridoxine for 15-18 days (30 mg, 100 mg and 200 mg daily). In vitro study of blood from seven normal volunteers was also performed, with before and after assaying of aspartate aminotransferase activity. RESULTS The in vivo study showed increasing aspartate aminotransferase saturation with increasing pyridoxine doses. 83% saturation was reached with 30 mg daily, 88% with 100 mg, and 93% with 200 mg after 20 days of oral supplementation. The in vitro study did not reach 100% saturation. CONCLUSIONS Neither in vivo nor in vitro study demonstrated thorough aspartate aminotransferase saturation with its coenzyme pyridoxal phosphate in red cells, from increasing pyridoxine supplementation. However, the 200-mg dose could be employed safely in vitamin B6-responsive sideroblastic anemia, myelofibrosis and Peyronies syndrome treatment. Although maximum saturation in circulating red cells is not achieved, erythroblasts and other nucleated and cytoplasmic organelles containing cells certainly will reach thorough saturation, which possibly explains the results obtained in these diseases.
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Affiliation(s)
- Marilena Oshiro
- Hematology Division, Instituto Adolfo Lutz, Av. Dr. Arnaldo 355, São Paulo, Brazil CEP 01246-000.
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11
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Chiang EPI, Bagley PJ, Roubenoff R, Nadeau M, Selhub J. Plasma pyridoxal 5'-phosphate concentration is correlated with functional vitamin B-6 indices in patients with rheumatoid arthritis and marginal vitamin B-6 status. J Nutr 2003; 133:1056-9. [PMID: 12672918 DOI: 10.1093/jn/133.4.1056] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Many patients with rheumatoid arthritis (RA) have low plasma pyridoxal-phosphate (PLP) but a normal erythrocyte aspartate aminotransferase activity coefficient (alpha EAST), a measure of vitamin B-6 status in the erythrocytes, compared with healthy subjects. The goal of the present study was to examine the correlations of PLP levels in these two compartments (plasma and erythrocytes) with other established indices of vitamin B-6 status, and to determine which indicator better reflects functional status of vitamin B-6 in patients with RA. Multiple indices of vitamin B-6 status were measured in 33 patients with RA. Plasma PLP, urinary 4-pyridoxic acid (4-PA), net increase in plasma total homocysteine after a methionine load (DeltatHcy) and net increase in urinary xanthurenic acid after a tryptophan load (DeltaXA) were log-transformed to reach normality for statistical analyses. We found that log-plasma PLP levels were inversely correlated with both log-DeltatHcy (r = -0.368, P = 0.035) and log-DeltaXA (r = -0.333, P = 0.05). Plasma PLP was not correlated with alpha EAST or urinary 4-PA excretion. In contrast, erythrocyte PLP was inversely correlated with alpha EAST (r = -0.431, P = 0.012) and positively correlated with log-4-PA (r = 0.475, P = 0.005), but erythrocyte PLP was not correlated with the outcomes of a methionine or tryptophan load test. Erythrocyte PLP and log-4-PA, but not plasma PLP, were correlated with dietary intake of vitamin B-6 after adjusting for protein intake (r = 0.420, P = 0.015 and r = 0.333, P = 0.05, respectively). We suggest that in patients with RA, plasma PLP levels are a better diagnostic indicator of functional vitamin B-6 status than erythrocyte PLP levels.
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Affiliation(s)
- En-Pei I Chiang
- Vitamin Metabolism and Aging Laboratory, Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston, MA 02111, USA
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12
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Hansen CM, Shultz TD. Stability of vitamin B-6-dependent aminotransferase activity in frozen packed erythrocytes is dependent on storage temperature. J Nutr 2001; 131:1581-3. [PMID: 11340119 DOI: 10.1093/jn/131.5.1581] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Pyridoxal 5'-phosphate (PLP) stimulation of erythrocyte alanine and aspartate aminotransferase (EALT, EAST) activities is a frequently used functional measure of vitamin B-6 status. Stability of enzyme activities and activity coefficients (AC, stimulated / unstimulated) was assessed in packed erythrocytes frozen at -20, -80 degrees C and under liquid nitrogen (-196 degrees C). Activities of EALT and EAST, with and without added PLP, were determined in fresh erythrocytes (d 0) and frozen samples on d 1, 7, 14, 28, 58 and 84. In -20 degrees C samples, EALT basal activity decreased 17 and 22% (P < or = 0.05 for both) by d 58 and 84, respectively, and EAST basal activity decreased 40% (P < or = 0.05) by d 58. In -80 and -196 degrees C samples, EALT and EAST basal activities did not change significantly. Activity coefficients did not differ significantly from d 0 at any storage temperature, but EAST-AC increased 9-19% (nonsignificant) in samples stored at -20 and -80 degrees C for 7 to 84 d. Additionally, EAST-AC was significantly higher in -20 than -80 and -196 degrees C samples on d 1 and 58, respectively. Erythrocytes may be frozen for 28 d at -20 degrees C and 84 d at -80 degrees C before analysis for EALT; for EAST, activity should be measured on fresh erythrocytes.
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Affiliation(s)
- C M Hansen
- Department of Food Science and Human Nutrition, Washington State University, Pullman, WA 99164-6376, USA
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13
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Abstract
The utilization of a usual dose of intravenously infused pyridoxine (100 mg pyridoxine hydrochloride) was investigated in ten healthy males. Blood plasma and erythrocytes were investigated by means of high-performance liquid chromatography. Detectable metabolites in blood plasma were pyridoxine, pyridoxal 5'-phosphate, pyridoxal and 4-pyridoxic acid. In erythrocytes pyridoxine, pyridoxal 5'-phosphate, pyridoxal, and pyridoxamine 5'-phosphate were found. From their concentration-time curves rate constants of elimination and invasion, volume of distribution (pyridoxine) and the areas under the curves were calculated. Values for concmax and tmax are reported. A comparison with earlier results of oral pyridoxine administration revealed a better utilization after intravenous than after oral application, i.e. a greater build-up of coenzyme forms. A regulatory phenomenon in erythrocytes caused by high doses of pyridoxine is described. In view of the potential toxicity of pyridoxine the doses used in parenteral nutrition are called into question.
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Affiliation(s)
- J Zempleni
- Institute of Nutritional Science, Justus-Liebig-University, Giessen, Germany
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14
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Fonda ML. Vitamin B6 metabolism and binding to proteins in the blood of alcoholic and nonalcoholic men. Alcohol Clin Exp Res 1993; 17:1171-8. [PMID: 8116826 DOI: 10.1111/j.1530-0277.1993.tb05223.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Blood obtained from nonalcoholic and alcoholic subjects was incubated with 100 nM [3H]pyridoxine to study its uptake and metabolism by erythrocytes and the binding of vitamin B6 metabolites to proteins in plasma and erythrocytes. Erythrocytes of the alcoholics accumulated tritium faster than those of the controls; however, they contained the same total amount of tritiated compounds by 15 min. After incubation for 30 min, the erythrocytes had converted most of the pyridoxine to pyridoxal phosphate and pyridoxal. Pyridoxal-P remained in the erythrocytes, and approximately 40% of the pyridoxal diffused into the plasma. [3H]Pyridoxal and [3H]pyridoxal-P levels in the erythrocytes and plasma of the alcoholics were similar to those in the controls. However, dialyzed hemolysates of the alcoholics had more [3H]pyridoxal and a lower percentage of [3H]pyridoxal-P than those of the controls. The total concentration of plasma pyridoxal-P was lower in the alcoholics than in the controls and did not change upon incubation of whole blood with pyridoxine or upon dialysis. The erythrocytes of the alcoholics and controls had similar concentrations of pyridoxal-P that increased 2.5-fold upon incubation of whole blood with pyridoxine for 30 min and returned to the initial concentrations upon dialysis. The amount of [3H]pyridoxal and [3H]pyridoxal-P bound to protein was assessed by treating hemolysate and plasma samples with borohydride before dialysis. More 3H was bound to protein in the erythrocytes than in the plasma. The amount of protein-bound 3H in the erythrocytes of the alcoholics was lower than that of the controls, whereas the amount of protein-bound 3H in plasma was similar in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- M L Fonda
- Department of Biochemistry, University of Louisville Health Sciences Center, KY 40292
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15
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van Wyk V, Luus HG, Heyns AD. The in vivo effect in humans of pyridoxal-5'-phosphate on platelet function and blood coagulation. Thromb Res 1992; 66:657-68. [PMID: 1519226 DOI: 10.1016/0049-3848(92)90042-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Vitamin B6 has an antithrombotic effect. This, based on the results of in vitro studies, has been attributed to an antiplatelet effect. We assessed the in vivo effect of vitamin B6 by measuring the effect of long-term administration of vitamin B6 on platelet function and blood coagulation. Vitamin B6 (pyridoxine hydrochloride), 100mg twice daily p.o. for fifteen days, was administered to 10 healthy volunteers. The bleeding time was measured before the first dose and 15 days after. A baseline value, the acute effect, chronic effect, and the acute-on-chronic effect of vitamin B6 was estimated by measuring platelet function. The following tests were performed: platelet aggregation induced by collagen, ADP and epinephrine; thromboxane A2 (TxA2)-production and prostacyclin inhibition of ADP-induced aggregation. The effects on the coagulation system were monitored by measuring: the prothrombin time, activated partial thromboplastin time and levels of coagulation factor. Vitamin B6 significantly prolonged the bleeding time from 4.1 +/- 1.1 minutes to 6.8 +/- 1.0 minutes (p = 0.0063). Aggregation of platelets with collagen was slightly but not significantly inhibited. Platelet aggregation induced with the agonists ADP or epinephrine was significantly inhibited by vitamin B6, and the platelets tended to aggregate at a slightly decreased rate. The mean TxA2-production was slightly, but not significantly, decreased. Vitamin B6 had no effect on the sensitivity of platelets to prostacyclin, or on the coagulation system. Our results indicate that the antithrombotic effects of vitamin B6 is limited to inhibition of platelet function; there was no measurable influence on coagulation. The results of this in vivo study are however such that clinical trials are warranted to further assess the efficacy of vitamin B6 as an antiplatelet drug.
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Affiliation(s)
- V van Wyk
- Department of Haematology, University of the Orange Free State, Bloemfontein, South Africa
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16
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Abstract
Biokinetic parameters of plasma pyridoxal-5'-phosphate (PLP) and pyridoxal (PL) disposition were studied in male Wistar rats aged 8 and 27 months kept from weaning on a purified diet containing 250 g casein and 6 mg pyridoxine.HCl per kg. Baseline plasma PLP concentration was lower in the older animals (514 +/- 56 nmol/L for young and 317 +/- 124 nmol/L for old animals), whereas baseline plasma PL concentration did not differ between age groups (average 235 nmol/L for both young and old animals). We hypothesized lower baseline plasma PLP in the older animals was caused by an increased PLP elimination rate, a decreased PLP synthesis rate, or a combination of these processes. Observations from earlier in vitro experiments suggest age-related changes occur in vitamin B-6 metabolizing enzyme activities. In the in vivo experiments described here no age-related difference in plasma PLP elimination rate nor in plasma PLP synthesis rate was observed to explain the observed decrease in plasma PLP concentration with age.
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Affiliation(s)
- W Bode
- TNO-CIVO Toxicology and Nutrition Institute Zeist, Department of Clinical Biochemistry, The Netherlands
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17
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Ubbink JB, Vermaak WJ, Delport R, Serfontein WJ, Bartel P. The relationship between vitamin B6 metabolism, asthma, and theophylline therapy. Ann N Y Acad Sci 1990; 585:285-94. [PMID: 2192613 DOI: 10.1111/j.1749-6632.1990.tb28061.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- J B Ubbink
- Department of Chemical Pathology, University of Pretoria, South Africa
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18
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Shephard GS, Van der Westhuizen L, Labadarios D. Analysis of vitamin B6 vitamers in human tissue by cation-exchange high-performance liquid chromatography. JOURNAL OF CHROMATOGRAPHY 1989; 491:226-34. [PMID: 2793974 DOI: 10.1016/s0378-4347(00)82837-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- G S Shephard
- Tygerberg Hospital, Department of Internal Medicine, University of Stellenbosch, South Africa
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19
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Ubbink JB, Schnell AM. High-performance liquid chromatographic assay of erythrocyte enzyme activity levels involved in vitamin B6 metabolism. JOURNAL OF CHROMATOGRAPHY 1988; 431:406-12. [PMID: 3243796 DOI: 10.1016/s0378-4347(00)83110-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- J B Ubbink
- Department of Chemical Pathology, University of Pretoria, South Africa
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20
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Vermaak WJ, Barnard HC, Van Dalen EM, Potgieter GM, Van Jaarsveld H, Myburgh SJ. Compartmentalization of pyridoxal-5'-phosphate during the acute phase of myocardial infarction. KLINISCHE WOCHENSCHRIFT 1988; 66:428-33. [PMID: 3398428 DOI: 10.1007/bf01745511] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Vitamin B6 nutritional status is assessed by measuring the plasma concentration of one of its vitamers, pyridoxal-phosphate (PLP). Several conditions, e.g., myocardial infarction (MI), can disturb the dynamic equilibrium between the different vitamers resulting in transiently low plasma PLP levels. An important question is whether these low plasma PLP levels observed during MI represent a transient state of deficiency and what the possible clinical consequences of such a fall in plasma PLP could be. Since the main metabolic function of PLP is to act as an intracellular coenzyme, it was decided to monitor the changes not only of PLP but also of PL (transport form of vitamin B6) in both the plasma and red blood cells (RBCs) in patients with myocardial infarctions (MI): 16 patients with proven MI were investigated measuring the aforementioned parameters at regular intervals. It was found that the approximately 40% fall in plasma PLP levels was accompanied by an equivalent increase in RBC PLP levels. Subsequently plasma PLP concentrations returned to normal but RBC PLP values were maintained at the newly elevated steady state (without any vitamin supplementation). Since membranes are impermeable to PLP, the only way in which PLP could have been redistributed to the intracellular compartment was through hydrolysis to PL and rephosphorylation once inside the RBCs. This compartmentalization could be an important adaptive response since it has been shown that PLP reduces O2 affinity of deoxygenated hemoglobin, thereby facilitating O2 delivery to the tissues.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- W J Vermaak
- Department of Chemical Pathology, Faculty of Medicine, University of the Orange Free State, Bloemfontein, South Africa
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21
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Fonda ML. Pyridoxamine (pyridoxine) phosphate oxidase activity in mammalian tissues. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. B, COMPARATIVE BIOCHEMISTRY 1988; 90:731-7. [PMID: 3248367 DOI: 10.1016/0305-0491(88)90327-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
1. Vitamin B6-sufficient rats had moderate pyridoxamine-P oxidase specific activities in heart, brain, kidney and liver, but no detectable activity in skeletal muscle. Vitamin B6-deficiency in rats resulted in a decreased oxidase activity in liver but no change in the activities in other tissues. 2. The pyridoxamine-P oxidase activity in vitamin B6-sufficient mice was high in liver, moderate in brain and kidney, and not measurable in skeletal muscle and heart. Vitamin B6-deficient, compared with control mice, had decreased oxidase activities in brain, kidney and liver. 3. Mouse erythrocytes took up pyridoxine more rapidly than did rat and human erythrocytes. 4. Mouse and human erythrocytes rapidly converted pyridoxine to pyridoxal-P. Rat, hamster and rabbit erythrocytes had appreciably lower pyridoxamine-P oxidase activity than did mouse and human erythrocytes.
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Affiliation(s)
- M L Fonda
- Department of Biochemistry, University of Louisville School of Medicine, Health Sciences Center, KY 40292
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22
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Henderson JM, Codner MA, Hollins B, Kutner MH, Merrill AH. The fasting B6 vitamer profile and response to a pyridoxine load in normal and cirrhotic subjects. Hepatology 1986; 6:464-71. [PMID: 3710434 DOI: 10.1002/hep.1840060324] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
This study established the fasting plasma and urine profiles of vitamin B6 in cirrhotics and assessed the response to an oral dose of pyridoxine. High-performance liquid chromatography was used to measure all vitameric coenzymatic and degradatory forms. In 31 patients with cirrhosis and 15 healthy controls, fasting plasma and 24-hr urine collection showed: plasma pyridoxal-5'-phosphate, the biologically active form, was significantly (p less than 0.001) reduced in cirrhotics (mean +/- S.D.: 5.7 +/- 3.2 ng per ml) compared to normals (14.2 +/- 7.5 ng per ml); plasma pyridoxal was detected in more cirrhotics (48%) than normals (28%); pyridoxic acid, the end catabolite, was significantly (p less than 0.05) lower in plasma of cirrhotics compared to normals, but 24-hr urine excretion was not different. Administration of 25 mg of pyridoxine to 7 cirrhotics and 5 normals showed the following plasma changes: pyridoxine rapidly peaked at 30 min and was totally cleared from plasma by 3 hr; plasma pyridoxal and pyridoxic acid increased in parallel up to 40-fold over baseline by 1 to 2 hr and rapidly fell toward baseline by 8 hr, and plasma pyridoxal-5'-phosphate, in contrast, increased significantly (p less than 0.05) from baseline by 60 min and was maintained above normal for 24 hr. The area under the plasma concentration vs. time curve (AUC) for pyridoxal-5'-phosphate was significantly (p less than 0.05) less for the cirrhotics than normals and showed a significant negative correlation to hepatocyte function and blood flow.(ABSTRACT TRUNCATED AT 250 WORDS)
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23
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24
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Corrons JLV, Pujades MA, Aguilar JL, Jou JM, Rozman C, Ester A. REPLY. Br J Haematol 1984. [DOI: 10.1111/j.1365-2141.1984.tb08563.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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25
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Corrons JLV, Pujades MA, Aguilar JL, Jou JM, Rozman C, Ester A. REPLY. Br J Haematol 1984. [DOI: 10.1111/j.1365-2141.1984.tb02951.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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26
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Temesvári P, Szilágyi I, Eck E, Boda D. Effects of an antenatal load of pyridoxine (vitamin B6) on the blood oxygen affinity and prolactin levels in newborn infants and their mothers. ACTA PAEDIATRICA SCANDINAVICA 1983; 72:525-9. [PMID: 6624427 DOI: 10.1111/j.1651-2227.1983.tb09765.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The effects of a loading dose of pyridoxine (100 mg) given intramuscularly or per os to 24 earlier non-supplemented pregnant women at term was investigated. The in vitro oxygen affinity (P50) and the prolactin level in both maternal and newborn blood was sampled. The blood P50 values were measured by a variant of "mixing method". Blood prolactin levels were determined by RIA. After pyridoxine administration, the maternal P50 values increased moderately and the newborns' cord blood P50 values increased significantly when compared with the control group's (number of cases 12) values. The decrease of blood oxygen affinity was most pronounced in the supplemented groups in newborns' capillary blood at the age of five days. The pyridoxine supplementation had no effect on the maternal and the newborns' cord blood prolactin level or on the daily amount of breast milk. Pyridoxine supplementation of the mother at labour may influence favourably the oxygen transport function of the newborn's blood and it may be especially advantageous in early postnatal adaptation disturbances of newborns.
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27
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28
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29
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Kark JA, Haut MJ, Hicks CU, McQuilkin CT, Reynolds RD. A rapid fluorometric assay for erythrocyte pyridoxal kinase. BIOCHEMICAL MEDICINE 1982; 27:109-20. [PMID: 6288024 DOI: 10.1016/0006-2944(82)90013-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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30
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Gross KC, Houghton MP, Roberts RB. Evaluation of blood culture media for isolation of pyridoxal-dependent Streptococcus mitior (mitis). J Clin Microbiol 1981; 14:266-72. [PMID: 7287885 PMCID: PMC271953 DOI: 10.1128/jcm.14.3.266-272.1981] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Nutritional variant streptococci identified as pyridoxal-dependent Streptococcus mitior (mitis) account for 5 to 6% of streptococcal endocarditis and may be a cause of "culture-negative" endocarditis. Hence, growth of three variant strains in 11 commercial blood culture broths was compared to that in fresh heart infusion broth. For simulation of clinical specimens, culture bottles were injected with 5 ml of human blood, inoculated with approximately 500 colony-forming units (CFU) per bottle, and monitored for 7 days with Gram stains and viable counts. Only Thiol broth (Difco Laboratories, Detroit, Mich.) supported growth without blood at this low inoculum. In media containing blood, maximal growth of 10(9) CFU/ml was reached within 2 days of incubation, and heavy turbidity was consistently observed in only heart infusion broth, Thiol broth, and media supplemented with pyridoxal hydrochloride. Columbia broth (BBL Microbiology Systems, Cockeysville, Md.) with increased cysteine, thioglycollate broth, and one brain heart infusion broth produced moderate growth (1 x 10(8) to 5 x 10(8) CFU/ml), whereas Columbia broth, another brain heart infusion broth, and two brands of tryptic soy broth showed fair growth (1 x 10(7) to 4 x 10(7) CFU/ml). The poor growth (1 x 10(6) to 3 x 10(6) CFU/ml) observed in three other brands of tryptic soy broth was often not apparent macroscopically or by Gram stain. Furthermore, on growth occurred in 40% of tryptic soy broth cultures inoculated with 50 CFU. Therefore, to ensure isolation of these variant streptococci from clinical blood cultures, a medium containing thiol compounds or supplemented with pyridoxal should be used. Subcultures should be made within 2 days of incubation to blood agar enriched with pyridoxal or containing a Staphylococcus sp. streak for satellitism.
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31
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Thanassi J, Nutter L, Meisler N, Commers P, Chiu J. Vitamin B6 metabolism in Morris hepatomas. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(19)69617-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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32
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Mehansho H, Henderson L. Transport and accumulation of pyridoxine and pyridoxal by erythrocytes. J Biol Chem 1980. [DOI: 10.1016/s0021-9258(19)70220-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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33
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Pyridoxine (pyridoxamine) 5'-phosphate oxidase in human red cells. Nutr Rev 1980; 38:380-1. [PMID: 7454153 DOI: 10.1111/j.1753-4887.1980.tb05949.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
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34
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Clements JE, Anderson BB. Glutathione reductase activity and pyridoxine (pyridoxamine) phosphate oxidase activity in the red cell. BIOCHIMICA ET BIOPHYSICA ACTA 1980; 632:159-63. [PMID: 7417521 DOI: 10.1016/0304-4165(80)90073-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The red-cell enzymes, glutathione reductase (FAD-dependent) and pyridoxine (pyridoxamine) phosphate oxidase (FMN-dependent), were studied in control subjects. The wide range in the glutathione reductase activity correlated inversely with the percentage stimulation by FAD added in vitro, and with pyridoxine (pyridoxamine) phosphate oxidase activity. Both enzymes were stimulated after ingestion of riboflavin. The results support the suggestion that the rate of metabolism of riboflavin in the red cell controls the activity of both enzymes, and the rate of red-cell metabolism of vitamin B-6.
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35
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Lumeng L, Lui A, Li TK. Plasma content of B6 vitamers and its relationship to hepatic vitamin B6 metabolism. J Clin Invest 1980; 66:688-95. [PMID: 7419716 PMCID: PMC371643 DOI: 10.1172/jci109906] [Citation(s) in RCA: 79] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The plasma content of B6 vitamers is governed by, among other factors, dietary supply and metabolic interconversion. This study examines the effect of pyridoxine supplementation on the plasma content of B6 vitamers and pyridoxic acid in man, and the metabolic conversion and release of B6 compounds in isolated rat hepatocytes. Six healthy human subjects were given 100 mg pyridoxine-HCl/d orally for 1--3 wk. Before pyridoxine supplementation, the mean total plasma level of B6 vitamers was 114 +/- 9 nM; and pyridoxal-P, pyridoxamine-P, pyridoxal, pyridoxine, and pyridoxamine accounted for 54, 3, 11, 27, and 5%, respectively. Plasma level of pyridoxic acid was 40 +/- 7 nM. Thus, pyridoxal-P is the principal B6 vitamer in plasma. During pyridoxine supplementation, mean plasma levels of the B6 vitamers and pyridoxic acid increased to 655 +/- 122 and 222 +/- 55 nM, respectively. The plasma content of pyridoxal-P and pyridoxic acid increased 6--7-fold and that of pyridoxal, 12-fold, but the pyridoxine level did not increase. Isolated hepatocytes, 1 g/15 ml, were incubated for 2 h with 3.33 microM [14C]pyridoxine (6 microCi/mumol). At zero time, the cells contained about 35 nmol pyridoxal-P and 25 nmol pyridoxamine-P. After 2 h incubation, the cellular content of pyridoxal-P and pyridoxamine-P did not change significantly, but the medium contained 5.9 nmol pyridoxal-P, 0.3 nmol pyridoxamine-P, 7.2 nmol pyridoxal, 26.6 nmol pyridoxine, 0.3 nmol pyridoxamine, and 7.5 nmol pyridoxic acid. Whereas the specific radioactivity of pyridoxal-P, pyridoxal, and pyridoxic acid in the medium approached that of [14C]pyridoxine, the specific radioactivity of cellular pyridoxal-P and pyridoxamine-P was only 20% of that of pyridoxine. Thus, newly synthesized pyridoxal-P is not freely exchangeable with endogenous pyridoxal-P, but is preferentially released or degraded to pyridoxal and pyridoxic acid. The latter B6 compounds are also released. These results suggest that orally ingested pyridoxine is rapidly metabolized in liver and its products are released into the circulation in the form of pyridoxal-P, pyridoxal, and pyridoxic acid.
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Mehansho H, Buss DD, Hamm MW, Henderson LM. Transport and metabolism of pyridoxine in rat liver. BIOCHIMICA ET BIOPHYSICA ACTA 1980; 631:112-23. [PMID: 7397240 DOI: 10.1016/0304-4165(80)90059-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Evidence, obtained with in situ perfused rat liver, indicated that pyridoxine is taken up from the perfusate by a non-concentrative process, followed by metabolic trapping. These conclusions were reached on the basis of the fact that at low concentrations (0.125 microM), the 3H of [3H]pyridoxine accumulated against a concentration gradient, but high concentrations (333 microM) of pyridoxine or 4-deoxypyridoxine prevented this apparent concentrative uptake. Under no conditions did the tissue water:perfusate concentration ratio of [3H]pyridoxine exceed unity. The perfused liver rapidly converted the labeled pyridoxine to pyridoxine phosphate, pyridoxal phosphate and pyridoxamine phosphate and released a substantial amount of pyridoxal and some pyridoxal phosphate into the perfusate. Since muscle and erythrocytes failed to oxidize pyridoxine phosphate to pyridoxal phosphate, it is suggested that the liver plays a major role in oxidizing dietary pyridoxine and pyridoxamine as their phosphate esters to supply pyridoxal phosphate which then reaches to other organs chiefly as circulating pyridoxal.
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Abstract
Successful application of pyridoxal 5'-phosphate (PLP) to restore the oxygen transport function of ACD-stored blood is described. PLP is readily incorporated into ACD-erythrocytes by both carrier-mediated transport (in which ATP may participate) and passive diffusion. Plasma proteins (up to 2.5%) and inorganic phosphate (up to 40 mM) do not affect the incorporation of PLP, though more than 25 mM inorganic phosphate is necessary for the maintenance of ATP levels. Increasing the PLP concentration and/or decreasing the packed cell volume in the medium, increases the incorporation of PLP. Incubation of erythrocytes with PLP at pH 7.0 is most suitable for incorporation of PLP and the maintenance of ATP levels. PLP incorporated into erythrocytes restores the oxygen transport function of the ACD-erythrocytes, though decreased haem--haem interaction is observed. A procedure for the clinical application of PLP-loaded erythrocytes is suggested.
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38
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Clements JE, Anderson BB. Pyridoxine (pyridoxamine) phosphate oxidase activity in the red cell. BIOCHIMICA ET BIOPHYSICA ACTA 1980; 613:401-9. [PMID: 7448195 DOI: 10.1016/0005-2744(80)90094-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A method has been developed for the measurement of red cell pyridoxine (pyridoxamine) phosphate oxidase activity. The more stable substrate, pyridoxamine phosphate, was incubated with a red cell haemolysate and the product pyridoxal phosphate was measured by Lactobacillus casei microbiological assay. A wide range of oxidase activities was found in control subjects (6-136 ng pyridoxal phosphate/g Hb x 10(-2)). There is a close correlation between the rate of conversion of pyridoxine to pyridoxal phosphate in whole blood and the oxidase activity. There was a marked increase in both after oral riboflavin. These results suggest that the oxidase plays a large part in the regulation of vitamin B-6 metabolism in red cells.
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39
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Anderson BB, O'Brien H, Griffin GE, Mollin DL. Hydrolysis of pyridoxal-5'-phosphate in plasma in conditions with raised alkaline phosphate. Gut 1980; 21:192-4. [PMID: 7399318 PMCID: PMC1420355 DOI: 10.1136/gut.21.3.192] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Hydrolysis of pyridoxal phosphate in plasma was demonstrated in patients with liver disease and other conditions with raised alkaline phosphatase, and this usually closely paralleled the alkaline phosphatase level, whether of liver or bone origin. The endogenous plasma pyridoxal phosphate was inversely related to the alkaline phosphatase, and plasma hydrolysis of pyridoxal phosphate may at least in part be responsible. Very large doses of vitamin B6 may be necessary to compensate for this hydrolysis.
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Fonda ML, Eggers DK, Mehta R. Vitamin B-6 metabolism in the blood of young adult and senescent mice. Exp Gerontol 1980; 15:465-72. [PMID: 7428866 DOI: 10.1016/0531-5565(80)90054-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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41
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Maeda N, Kon K, Sekiya M, Shiga T. Restoration of the poor oxygen transport function of ACD-stored blood by pyridoxal 5'-phosphate. EXPERIENTIA 1979; 35:1245-6. [PMID: 488295 DOI: 10.1007/bf01963316] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Pyridoxal 5'-phosphate is easily incorporated into ACD-stored erythrocytes without decrease of ATP, and restores the poor oxygen transport function with a similar effect to 2,3'-diphosphoglycerate.
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Anderson BB, Perry GM, Modell CB, Child JA, Mollin DL. Abnormal red-cell metabolism of pyridoxine associated with beta-thalassaemia. Br J Haematol 1979; 41:497-507. [PMID: 435399 DOI: 10.1111/j.1365-2141.1979.tb05887.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Red-cell conversion of pyridoxine to pyridoxal phosphate was studied in control subjects, and patients with heterozygous and homozygous beta-thalassaemia. In 7% of control subjects the rate of pyridoxine conversion was well below the range found in the other control subjects (5.0-8.6%, mean 6.5%/g Hb x 10(-2)) but in heterozygous beta-thalassaemia was below that range in 63% of the patients. The conversion rate was also slow or borderline in the majority of patients with severe transfusion-dependent homozygous beta-thalassaemia, in spite of the presence of some donor cells; but was normal, or fast as in other anaemias, in all but one patient with mild homozygous thalassaemia. There was a much higher incidence of a slow conversion rate in the parents of the severe homozygotes than in parents of the mild homozygotes, illustrating the familial pattern. This supports our view that the red-cell conversion rate of pyridoxine is an inherited characteristic, independent of thalassaemia. The cause of a reduced rate of pyridoxine conversion was investigated. The increase to a normal rate following riboflavin ingestion suggests a defect in the activity of the flavin mononucleotide (FMN)-dependent pyridoxine phosphate oxidase.
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Ibrahim NG, Spieler PJ, Freedman ML. Ethanol inhibition of rabbit reticulocyte haem synthesis at the level of delta-aminolaevulinic acid synthetase. Br J Haematol 1979; 41:235-43. [PMID: 218606 DOI: 10.1111/j.1365-2141.1979.tb05852.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Ethanol inhibition of rabbit reticulocyte synthesis occurs as a result of a decrease in haem synthesis. The present study therefore was undertaken in order to localize the inhibitory site of ethanol on the haem biosynthetic pathway. Ethanol (0.05--0.15 M) inhibition of reticulocyte protein synthesis was prevented by simultaneous incubation with 0.025--1 mM delta-aminolaevulinic acid (ALA). Ethanol inhibited both 14C-glycine and 14C-ALA incorporation into haem. However, the extent of haem formation with 14C-ALA as substrate in the presence of ethanol was still equal to that when 14C-glycine was used. These data suggest that ethanol inhibits the haem synthetic pathway at several loci, but that the decrease in haem synthesis, responsible for the decrease in protein synthesis, is due to the inhibition at the rate-limiting enzyme, delta-aminolaevulinic acid synthetase (ALA-S). To confirm this, ALA-S activity was then directly measured in intact reticulocytes, and it was shown that ethanol indeed inhibited its activity. The inhibition of ALA-S was prevented by 10(-4) M dibutyryl cyclic AMP (db cAMP) or theophylline, agents which elevate intracellular cAMP and which have previously been shown to prevent and reverse ethanol inhibition of haem and protein synthesis. Thus, it appears that cAMP protects against ethanol toxicity by preventing inhibition of ALA-S.
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Ponka P, Borová J, Neuwirt J, Fuchs O. Mobilization of iron from reticulocytes. Identification of pyridoxal isonicotinoyl hydrazone as a new iron chelating agent. FEBS Lett 1979; 97:317-21. [PMID: 761636 DOI: 10.1016/0014-5793(79)80111-8] [Citation(s) in RCA: 155] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Subbardo K, Kuchibhotla J, Kakkar VV. Pyridoxal 5'-phosphate--a new physiological inhibitor of blood coagulation and platelet function. Biochem Pharmacol 1979; 28:531-4. [PMID: 426874 DOI: 10.1016/0006-2952(79)90248-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Chapman SK, Maren TH. A search for the function of human carbonic anhydrase B. BIOCHIMICA ET BIOPHYSICA ACTA 1978; 527:272-6. [PMID: 102361 DOI: 10.1016/0005-2744(78)90277-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Because of the very high activity and abundance of human red cell carbonic anhydrase C (carbamate hydrolase, EC 4.2.1.1), it seemed likely that the second isozyme, B, might not be essential for CO2 metabolism. It was then found that physiological concentrations of Cl- inhibited catalysis of CO2 hydration by the B enzyme (but not by type C), suggesting further that type B does not function in vivo as a carbonic anhydrase. The versatility of the catalytic activity of carbonic anhydrase for a number of 'artificial' substrates suggested that enzyme B may be utilized in reactions of intermediary metabolism. A number of hydration, dehydration, decarboxylation, kinase, and phosphatase systems were tested to determine a possible physiological function for the enzyme. Results with eighteen possible substrates were negative and the possibility is discussed that mammalian carbonic anhydrase B is an evolutionary accident.
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Spector R, Greenwald L. Transport and metabolism of vitamin B6 in rabbit brain and choroid plexus. J Biol Chem 1978. [DOI: 10.1016/s0021-9258(17)38084-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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