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Lemli B, Lomozová Z, Huber T, Lukács A, Poór M. Effects of Heme Site (FA1) Ligands Bilirubin, Biliverdin, Hemin, and Methyl Orange on the Albumin Binding of Site I Marker Warfarin: Complex Allosteric Interactions. Int J Mol Sci 2022; 23:ijms232214007. [PMID: 36430492 PMCID: PMC9694159 DOI: 10.3390/ijms232214007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 11/09/2022] [Accepted: 11/11/2022] [Indexed: 11/16/2022] Open
Abstract
Human serum albumin (HSA) is the most abundant plasma protein in circulation. The three most important drug-binding sites on HSA are Sudlow's Site I (subdomain IIA), Sudlow's Site II (subdomain IIIA), and Heme site (subdomain IB). Heme site and Site I are allosterically coupled; therefore, their ligands may be able to allosterically modulate the binding affinity of each other. In this study, the effects of four Heme site ligands (bilirubin, biliverdin, hemin, and methyl orange) on the interaction of the Site I ligand warfarin with HSA were tested, employing fluorescence spectroscopic, ultrafiltration, and ultracentrifugation studies. Our major results/conclusions are the following. (1) Quenching studies indicated no relevant interaction, while the other fluorescent model used suggested that each Heme site ligand strongly decreases the albumin binding of warfarin. (2) Ultrafiltration and ultracentrifugation studies demonstrated the complex modulation of warfarin-HSA interaction by the different Heme site markers; for example, bilirubin strongly decreased while methyl orange considerably increased the bound fraction of warfarin. (3) Fluorescence spectroscopic studies showed misleading results in these diligand-albumin interactions. (4) Different Heme site ligands can increase or decrease the albumin binding of warfarin and the outcome can even be concentration dependent (e.g., biliverdin and hemin).
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Affiliation(s)
- Beáta Lemli
- Department of Pharmacology, Faculty of Pharmacy, University of Pécs, Rókus u. 2, H-7624 Pécs, Hungary
- Green Chemistry Research Group, János Szentágothai Research Centre, University of Pécs, Ifjúság útja 20, H-7624 Pécs, Hungary
| | - Zuzana Lomozová
- The Department of Pharmacognosy and Pharmaceutical Botany, Faculty of Pharmacy in Hradec Králové, Charles University, Akademika Heyrovského 1203, 500 05 Hradec Králové, Czech Republic
| | - Tamás Huber
- Department of Biophysics, Medical School, University of Pécs, Szigeti út 12, H-7624 Pécs, Hungary
| | - András Lukács
- Department of Biophysics, Medical School, University of Pécs, Szigeti út 12, H-7624 Pécs, Hungary
| | - Miklós Poór
- Department of Pharmacology, Faculty of Pharmacy, University of Pécs, Rókus u. 2, H-7624 Pécs, Hungary
- Lab-on-a-Chip Research Group, János Szentágothai Research Centre, University of Pécs, Ifjúság útja 20, H-7624 Pécs, Hungary
- Correspondence: ; Tel.: +36-72-501-500 (ext. 28316)
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Tramarin A, Tedesco D, Naldi M, Baldassarre M, Bertucci C, Bartolini M. New insights into the altered binding capacity of pharmaceutical-grade human serum albumin: site-specific binding studies by induced circular dichroism spectroscopy. J Pharm Biomed Anal 2019; 162:171-178. [DOI: 10.1016/j.jpba.2018.09.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 09/03/2018] [Accepted: 09/11/2018] [Indexed: 12/16/2022]
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Interaction of the mycotoxin metabolite dihydrocitrinone with serum albumin. Mycotoxin Res 2018; 35:129-139. [PMID: 30426325 DOI: 10.1007/s12550-018-0336-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 11/04/2018] [Accepted: 11/06/2018] [Indexed: 01/30/2023]
Abstract
Citrinin (CIT) is a nephrotoxic mycotoxin produced by Penicillium, Monascus, and Aspergillus species. CIT appears as a contaminant in cereals, cereal-based products, fruits, nuts, and spices. During the biotransformation of CIT, its major urinary metabolite dihydrocitrinone (DHC) is formed. Albumin interacts with several compounds (including mycotoxins) affecting their tissue distribution and elimination. CIT-albumin interaction is known; however, the complex formation of DHC with albumin has not been reported previously. In this study, we aimed to investigate the interaction of DHC with albumin, employing fluorescence spectroscopy, circular dichroism, and molecular modeling studies. Furthermore, species differences and thermodynamics of the interaction as well as the effects of albumin on the acute in vitro toxicity of DHC and CIT were also tested. Our main observations/conclusions are as follows: (1) Fluorescence signal of DHC is strongly enhanced by albumin. (2) Formation of DHC-albumin complexes is supported by both fluorescence spectroscopic and circular dichroism studies. (3) DHC forms similarly stable complexes with human albumin (K~105 L/mol) as CIT. (4) DHC-albumin interaction did not show significant species differences (tested with human, bovine, porcine, and rat albumins). (5) Based on modeling studies and investigations with site markers, DHC occupies the Heme binding site (subdomain IB) on human albumin. (6) The presence of albumin significantly decreased the acute in vitro cytotoxic effects of both DHC and CIT on MDCK cell line.
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Interaction of 2'R-ochratoxin A with Serum Albumins: Binding Site, Effects of Site Markers, Thermodynamics, Species Differences of Albumin-binding, and Influence of Albumin on Its Toxicity in MDCK Cells. Toxins (Basel) 2018; 10:toxins10090353. [PMID: 30200461 PMCID: PMC6162703 DOI: 10.3390/toxins10090353] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 08/17/2018] [Accepted: 08/27/2018] [Indexed: 01/02/2023] Open
Abstract
Ochratoxin A (OTA) is a nephrotoxic mycotoxin. Roasting of OTA-contaminated coffee results in the formation of 2′R-ochratoxin A (2′R-OTA), which appears in the blood of coffee drinkers. Human serum albumin (HSA) binds 2′R-OTA (and OTA) with high affinity; therefore, albumin may influence the tissue uptake and elimination of ochratoxins. We aimed to investigate the binding site of 2′R-OTA (verses OTA) in HSA and the displacing effects of site markers to explore which molecules can interfere with its albumin-binding. Affinity of 2′R-OTA toward albumins from various species (human, bovine, porcine and rat) was tested to evaluate the interspecies differences regarding 2′R-OTA-albumin interaction. Thermodynamic studies were performed to give a deeper insight into the molecular background of the complex formation. Besides fluorescence spectroscopic and modeling studies, effects of HSA, and fetal bovine serum on the cytotoxicity of 2′R-OTA and OTA were tested in MDCK kidney cell line in order to demonstrate the influence of albumin-binding on the cellular uptake of ochratoxins. Site markers displaced more effectively 2′R-OTA than OTA from HSA. Fluorescence and binding constants of 2′R-OTA-albumin and OTA-albumin complexes showed different tendencies. Albumin significantly decreased the cytotoxicity of ochratoxins. 2′R-OTA, even at sub-toxic concentrations, increased the toxic action of OTA.
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Khrenova MG, Kulakova AM, Nemukhin AV. Competition between two cysteines in covalent binding of biliverdin to phytochrome domains. Org Biomol Chem 2018; 16:7518-7529. [DOI: 10.1039/c8ob02262c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In this work, we disclose a mechanism of competing chemical reactions of protein assembly for a bacterial phytochrome using modern methods of molecular modeling.
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Affiliation(s)
- Maria G. Khrenova
- Department of Chemistry
- Lomonosov Moscow State University
- Moscow
- Russian Federation
- Federal Research Center of Biotechnology
| | - Anna M. Kulakova
- Department of Chemistry
- Lomonosov Moscow State University
- Moscow
- Russian Federation
| | - Alexander V. Nemukhin
- Department of Chemistry
- Lomonosov Moscow State University
- Moscow
- Russian Federation
- Emanuel Institute of Biochemical Physics
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Investigation of Non-Covalent Interactions of Aflatoxins (B1, B2, G1, G2, and M1) with Serum Albumin. Toxins (Basel) 2017; 9:toxins9110339. [PMID: 29068381 PMCID: PMC5705954 DOI: 10.3390/toxins9110339] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 10/15/2017] [Accepted: 10/20/2017] [Indexed: 01/30/2023] Open
Abstract
Aflatoxins are widely spread mycotoxins produced mainly by Aspergillus species. Consumption of aflatoxin-contaminated foods and drinks causes serious health risks for people worldwide. It is well-known that the reactive epoxide metabolite of aflatoxin B1 (AFB1) forms covalent adducts with serum albumin. However, non-covalent interactions of aflatoxins with human serum albumin (HSA) are poorly characterized. Thus, in this study the complex formation of aflatoxins was examined with HSA applying spectroscopic and molecular modelling studies. Our results demonstrate that aflatoxins form stable complexes with HSA as reflected by binding constants between 2.1 × 104 and 4.5 × 104 dm3/mol. A binding free energy value of −26.90 kJ mol−1 suggests a spontaneous binding process between AFB1 and HSA at room-temperature, while the positive entropy change of 55.1 JK−1 mol−1 indicates a partial decomposition of the solvation shells of the interacting molecules. Modeling studies and investigations with site markers suggest that Sudlow’s Site I of subdomain IIA is the high affinity binding site of aflatoxins on HSA. Interaction of AFB1 with bovine, porcine, and rat serum albumins was also investigated. Similar stabilities of the examined AFB1-albumin complexes were observed suggesting the low species differences of the albumin-binding of aflatoxins.
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Funahashi A, Komatsu M, Furukawa T, Yoshizono Y, Yoshizono H, Orikawa Y, Takumi S, Shiozaki K, Hayashi S, Kaminishi Y, Itakura T. Eel green fluorescent protein is associated with resistance to oxidative stress. Comp Biochem Physiol C Toxicol Pharmacol 2016; 181-182:35-9. [PMID: 26746389 DOI: 10.1016/j.cbpc.2015.12.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 12/16/2015] [Accepted: 12/19/2015] [Indexed: 11/24/2022]
Abstract
Green fluorescent protein (GFP) from eel (Anguilla japonica) muscle (eelGFP) is unique in the vertebrates and requires bilirubin as a ligand to emit fluorescence. This study was performed to clarify the physiological function of the unique GFP. Investigation of susceptibility to oxidative stress was carried out using three types of cell lines including jellyfish (Aequorea coerulescens) GFP (jfGFP)-, or eel GFP (eelGFP)-expressing HEK293 cells, and control vector-transfected HEK293 cells. Binding of eelGFP to bilirubin was confirmed by the observation of green fluorescence in HEK293-eelGFP cells. The growth rate was compared with the three types of cells in the presence or absence of phenol red which possessed antioxidant activity. The growth rates of HEK293-CV and HEK293-jfGFP under phenol red-free conditions were reduced to 52 and 31% of those under phenol red. Under the phenol red-free condition, HEK293-eelGFP had a growth rate of approximately 70% of the phenol red-containing condition. The eelGFP-expressing cells were approximately 2-fold resistant to oxidative stress such as H2O2 exposure. The fluorescence intensity partially decreased or disappeared after exposure to H2O2, and heterogeneous intensity of fluorescence was also observed in isolated eel skeletal muscle cells. These results suggested eelGFP, but not jfGFP, coupled with bilirubin provided the antioxidant activity to the cells as compared to non-bound free bilirubin.
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Affiliation(s)
- Aki Funahashi
- Laboratory of Marine Biotechnology, Faculty of Fisheries, Kagoshima University, 4-50-20 Shimoarata, Kagoshima 890-0056, Japan
| | - Masaharu Komatsu
- Division of Food and Chemical Biology, Faculty of Fisheries, Kagoshima University, 4-50-20 Shimoarata, Kagoshima 890-0056, Japan.
| | - Tatsuhiko Furukawa
- Department of Molecular Oncology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544, Japan; Center for the Research of Advanced Diagnosis and Therapy of Cancer, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544, Japan
| | - Yuki Yoshizono
- Division of Food and Chemical Biology, Faculty of Fisheries, Kagoshima University, 4-50-20 Shimoarata, Kagoshima 890-0056, Japan
| | - Hikari Yoshizono
- Division of Food and Chemical Biology, Faculty of Fisheries, Kagoshima University, 4-50-20 Shimoarata, Kagoshima 890-0056, Japan
| | - Yasuhiro Orikawa
- Division of Food and Chemical Biology, Faculty of Fisheries, Kagoshima University, 4-50-20 Shimoarata, Kagoshima 890-0056, Japan
| | - Shota Takumi
- Division of Food and Chemical Biology, Faculty of Fisheries, Kagoshima University, 4-50-20 Shimoarata, Kagoshima 890-0056, Japan; Department of Domestic Science, Kagoshima Women's College, Kagoshima 890-8565, Japan
| | - Kazuhiro Shiozaki
- Division of Food and Chemical Biology, Faculty of Fisheries, Kagoshima University, 4-50-20 Shimoarata, Kagoshima 890-0056, Japan
| | - Seiichi Hayashi
- Division of Food and Chemical Biology, Faculty of Fisheries, Kagoshima University, 4-50-20 Shimoarata, Kagoshima 890-0056, Japan
| | - Yoshio Kaminishi
- Laboratory of Marine Biotechnology, Faculty of Fisheries, Kagoshima University, 4-50-20 Shimoarata, Kagoshima 890-0056, Japan
| | - Takao Itakura
- Laboratory of Marine Biotechnology, Faculty of Fisheries, Kagoshima University, 4-50-20 Shimoarata, Kagoshima 890-0056, Japan
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Photo-isomerization and oxidation of bilirubin in mammals is dependent on albumin binding. Anal Biochem 2015; 490:34-45. [PMID: 26297581 DOI: 10.1016/j.ab.2015.08.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 08/02/2015] [Accepted: 08/05/2015] [Indexed: 11/23/2022]
Abstract
The bilirubin (BR) photo-conversion in the human body is a protein-dependent process; an effective photo-isomerization of the potentially neurotoxic Z,Z-BR as well as its oxidation to biliverdin in the antioxidant redox cycle is possible only when BR is bound on serum albumin. We present a novel analytical concept in the study of linear tetrapyrroles metabolic processes based on an in-depth mapping of binding sites in the structure of human serum albumin (HSA). A combination of fluorescence spectroscopy, circular dichroism (CD) spectroscopy, and molecular modeling methods was used for recognition of the binding site for BR, its derivatives (mesobilirubin and bilirubin ditaurate), and the products of the photo-isomerization and oxidation (lumirubin, biliverdin, and xanthobilirubic acid) on HSA. The CD spectra and fluorescent quenching of the Trp-HSA were used to calculate the binding constants. The results of the CD displacement experiments performed with hemin were interpreted together with the findings of molecular docking performed on the pigment-HSA complexes. We estimated that Z,Z-BR and its metabolic products bind on two independent binding sites. Our findings support the existence of a reversible antioxidant redox cycle for BR and explain an additional pathway of the photo-isomerization process (increase of HSA binding capacity; the excess free [unbound] BR can be converted and also bound to HSA).
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Minic SL, Milcic M, Stanic-Vucinic D, Radibratovic M, Sotiroudis TG, Nikolic MR, Velickovic TĆ. Phycocyanobilin, a bioactive tetrapyrrolic compound of blue-green alga Spirulina, binds with high affinity and competes with bilirubin for binding on human serum albumin. RSC Adv 2015. [DOI: 10.1039/c5ra05534b] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
High affinity, stereo-selective binding of phycocyanobilinM-conformer to HSA, and its competition with bilirubin, warfarin and hemin for the binding to protein.
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Affiliation(s)
- Simeon L. Minic
- Department of Biochemistry
- Center of Excellence for Molecular Food Sciences
- Faculty of Chemistry
- University of Belgrade
- 11000 Belgrade
| | - Miloš Milcic
- Department of Biochemistry
- Center of Excellence for Molecular Food Sciences
- Faculty of Chemistry
- University of Belgrade
- 11000 Belgrade
| | - Dragana Stanic-Vucinic
- Department of Biochemistry
- Center of Excellence for Molecular Food Sciences
- Faculty of Chemistry
- University of Belgrade
- 11000 Belgrade
| | - Milica Radibratovic
- Institute of Chemistry
- Technology and Metallurgy – Center for Chemistry
- University of Belgrade
- 11000 Belgrade
- Serbia
| | - Theodore G. Sotiroudis
- Institute of Biology
- Medicinal Chemistry and Biotechnology
- National Hellenic Research Foundation
- 11635 Athens
- Greece
| | - Milan R. Nikolic
- Department of Biochemistry
- Center of Excellence for Molecular Food Sciences
- Faculty of Chemistry
- University of Belgrade
- 11000 Belgrade
| | - Tanja Ćirković Velickovic
- Department of Biochemistry
- Center of Excellence for Molecular Food Sciences
- Faculty of Chemistry
- University of Belgrade
- 11000 Belgrade
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Zsila F. Subdomain IB Is the Third Major Drug Binding Region of Human Serum Albumin: Toward the Three-Sites Model. Mol Pharm 2013; 10:1668-82. [DOI: 10.1021/mp400027q] [Citation(s) in RCA: 233] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ferenc Zsila
- Laboratory of Chemical Pharmacology,
Institute of Molecular
Pharmacology, Research Centre for Natural Sciences, H-1025 Budapest, Pusztaszeri út 59-67, Hungary
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11
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Ahlfors CE, Wennberg RP, Ostrow JD, Tiribelli C. Unbound (free) bilirubin: improving the paradigm for evaluating neonatal jaundice. Clin Chem 2009; 55:1288-99. [PMID: 19423734 DOI: 10.1373/clinchem.2008.121269] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND The serum or plasma total bilirubin concentration (B(T)) has long been the standard clinical laboratory test for evaluating neonatal jaundice, despite studies showing that B(T) correlates poorly with acute bilirubin encephalopathy (ABE) and its sequelae including death, classical kernicterus, or bilirubin-induced neurological dysfunction (BIND). The poor correlation between B(T) and ABE is commonly attributed to the confounding effects of comorbidities such as hemolytic diseases, prematurity, asphyxia, or infection. Mounting evidence suggests, however, that B(T) inherently performs poorly because it is the plasma non-protein-bound (unbound or free) bilirubin concentration (B(f)), rather than B(T), that is more closely associated with central nervous system bilirubin concentrations and therefore ABE and its sequelae. CONTENT This article reviews (a) the complex relationship between serum or plasma bilirubin measurements and ABE, (b) the history underlying the limited use of B(f) in the clinical setting, (c) the peroxidase method for measuring B(f) and technical and other issues involved in adapting the measurement to routine clinical use, (d) clinical experience using B(f) in the management of newborn jaundice, and (e) the value of B(f) measurements in research investigating bilirubin pathochemistry. SUMMARY Increasing evidence from clinical studies, clinical experience, and basic research investigating bilirubin neurotoxicity supports efforts to incorporate B(f) expeditiously into the routine evaluation of newborn jaundice.
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Affiliation(s)
- Charles E Ahlfors
- Division of Neonatology, Department of Pediatrics, Stanford University School of Medicine, Palo Alto, CA, USA.
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Effect of storage and freezing on unbound bilirubin measurement. Clin Chim Acta 2008; 396:56-7. [PMID: 18644357 DOI: 10.1016/j.cca.2008.06.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2008] [Revised: 06/24/2008] [Accepted: 06/25/2008] [Indexed: 10/21/2022]
Abstract
BACKGROUND Unbound bilirubin (Bf) is a better predictor of bilirubin toxicity than total serum bilirubin (TSB) in the postnatal period. The Food and Drug Administration approved peroxidase test for Bf analysis is not currently available in clinical laboratories. The samples are often stored at varying temperature and for varying duration before Bf analysis. METHODS We evaluated the effect of storing blood samples up to 1 month at -20 degrees C and -80 degrees C on Bf measurement. In a subset of samples collected for neonates enrolled in a prospective Bf study, TSB (micromol/l) and Bf (micromol/l) were measured by the peroxidase test and then the samples were immediately frozen at -20 degrees C (n=10) or -80 degrees C (n=10) for either 2 weeks or at -20 degrees C (n=16) or -80 degrees C (n=10) for 1 month. After the designated freezing period, the samples were thawed and TSB and Bf measured again. RESULTS There was no effect of storage for 2 weeks at either -20 degrees C or -80 degrees C on Bf measurement. There appears to be no effect on Bf after storage at -80 degrees C for a month. However, there was significant decrease in Bf after storage at -20 degrees C for a month. CONCLUSIONS The results of this study suggest that blood samples for Bf measurement should be analyzed within 2 weeks after collection and storage at -20 degrees C.
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Soltés L, Sebille B. Reversible binding interactions between the tryptophan enantiomers and albumins of different animal species as determined by novel high performance liquid chromatographic methods: an attempt to localize the D- and L-tryptophan binding sites on the human serum albumin polypeptide chain by using protein fragments. Chirality 1997; 9:373-9. [PMID: 9275316 DOI: 10.1002/(sici)1520-636x(1997)9:4<373::aid-chir10>3.0.co;2-k] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The stereoselectivity of the reversible binding interactions between the D- and L-tryptophan enantiomers and serum albumins of different animal species and fragments of human serum albumin (HSA) was investigated by applying three novel high performance liquid chromatographic (HPLC) arrangements. The separations were performed by means of 1) an achiral (diol-bond), 2) a chiral (bovine serum albumin-bond) silica gel sorbent, and 3) a column switching technique which uses both the diol- and HSA-bond HPLC stationary phases. A polarimetric detector and/or an ultraviolet (UV) spectrophotometer were used to monitor the separation process. HPLC arrangement 3 allowed the evaluation of enantioselective binding for D- and L-tryptophan to different albumins and albumin fragments. At present, column switching can be considered the technique of the broadest applicability for investigating the reversible binding interactions between a protein and drug enantiomers.
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Affiliation(s)
- L Soltés
- Institute of Experimental Pharmacology, Slovak Academy of Sciences, Bratislava, Slovak Republic
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14
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McPhee F, Caldera PS, Bemis GW, McDonagh AF, Kuntz ID, Craik CS. Bile pigments as HIV-1 protease inhibitors and their effects on HIV-1 viral maturation and infectivity in vitro. Biochem J 1996; 320 ( Pt 2):681-6. [PMID: 8973584 PMCID: PMC1217983 DOI: 10.1042/bj3200681] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Using recently developed molecular-shape description algorithms, we searched the Available Chemical Directory for known compounds similar in shape to the potent HIV-1 protease inhibitor Merck L-700,417; 15 compounds most similar in shape to the inhibitor were selected for testing in vitro. Four of these inhibited the protease at 100 microM or less and the most active of the four were the naturally occurring pigments biliverdin and bilirubin. Biliverdin and bilirubin inhibited recombinant HIV-1 protease in vitro at pH 7.8 with K1 values of approx. 1 microM, and also inhibited HIV-2 and simian immunodeficiency virus proteases. The related pyrrolic pigments stercobilin, urobilin, biliverdin dimethyl ester and xanthobilirubic acid showed similar inhibitory activity at low micromolar concentrations. Biliverdin, bilirubin and xanthobilirubic acid did not inhibit viral polyprotein processing in cultured cells, but they reduced viral infectivity significantly. At 100 microM, xanthobilirubic acid affected viral assembly, resulting in a 50% decrease in the generation of infectious particles. In contrast, at the same concentrations biliverdin and bilirubin exerted little or no effect on viral assembly but blocked infection of HeLaT4 cells by 50%. These results suggest that bile pigments might be a new class of potential lead compounds for developing protease inhibitors and they raise the question of whether hyperbilirubinaemia can influence the course of HIV infection.
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Affiliation(s)
- F McPhee
- Department of Pharmaceutical Chemistry, University of California, San Francisco, USA
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15
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High performance liquid chromatographic screening methods for revealing the stereoselectivity of reversible interactions between ligand enantiomers and a counterpart substance. Chromatographia 1994. [DOI: 10.1007/bf02269633] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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16
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Šoltés L, Séabille B. Study of Macrobiomolecule-Ligand Interactions by Liquid-Chromatographic Separation Methods Under Equilibrium and Nonequilibrium Conditions. ACTA ACUST UNITED AC 1994. [DOI: 10.1080/10826079408013542] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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17
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Minchiotti L, Galliano M, Zapponi MC, Tenni R. The structural characterization and bilirubin-binding properties of albumin Herborn, a [Lys240-->Glu] albumin mutant. EUROPEAN JOURNAL OF BIOCHEMISTRY 1993; 214:437-44. [PMID: 8513793 DOI: 10.1111/j.1432-1033.1993.tb17939.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We report the molecular defect of albumin Herborn, a new genetic variant of human serum albumin which has been found in Germany. Isoelectric focusing analysis of CNBr fragments from the purified variant allowed us to localize the mutation in fragment CNBr 3 (residues 124-298). This fragment was isolated on a preparative scale and subjected to tryptic and V8 protease digestion. Sequence determination of the abnormal tryptic and V8 peptides revealed that the variant arises from the substitution Lys240-->Glu. The -2 charge change of albumin Herborn, which is probably due to a A-->G transition in the first position of the corresponding codon in the structural gene, has no significant effect on its electrophoretic mobility under non-denaturating conditions. Therefore we have assumed that residue 240, which has been implicated in the bilirubin primary binding site (Jacobsen, C. (1978) Biochem. J. 171, 453-459), is buried. The binding of bilirubin and biliverdin by albumin Herborn was quantified using the fluorescence quenching method. The apparent equilibrium association constants (Ka +/- SD) and the number of high-affinity binding sites (n) of the defatted variant for bilirubin and biliverdin were Ka = 1.03 +/- 0.18 x 10(8) M-1, n = 1.07; and Ka = 7.48 +/- 1.10 x 10(6) M-1, n = 1.01, respectively. The Ka values are about 93.3% and 99.1% of the values found for the normal protein under the same conditions. These results strongly suggest that Lys240 of human serum albumin is not the basic residue involved in ion pairing with one of the carboxylate groups of bilirubin at its high-affinity site.
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Affiliation(s)
- L Minchiotti
- Dipartimento di Biochimica, Università di Pavia, Italy
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18
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Trull FR, Ibars O, Lightner DA. Conformation inversion of bilirubin formed by reduction of the biliverdin-human serum albumin complex: evidence from circular dichroism. Arch Biochem Biophys 1992; 298:710-4. [PMID: 1416999 DOI: 10.1016/0003-9861(92)90470-h] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
As shown by circular dichroism spectroscopy, biliverdin preferentially adopts an M-helicity conformation on human serum albumin in aqueous buffer, pH 7.5, whereas biliverdin exhibits only a weak preference for the P-helicity conformation on bovine serum albumin at the same pH. Upon rapid reduction of the complexes with sodium borohydride, P-helicity bilirubin-IX alpha is obtained on the human albumin complex, and M-helicity bilirubin-IX alpha is obtained on the bovine serum albumin complex. Thus, biliverdin in effect undergoes an inversion of chirality upon reduction. Since the reduction did not afford a rubin with the same helicity as that of the verdin, the observations point to a hitherto undetected conformational mobility of albumin-bound bilirubin.
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Affiliation(s)
- F R Trull
- Departament de Química Orgànica, Universitat de Barcelona, Catalunya, Spain
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19
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Soltés L, Sébille B, Fügedi A. High-performance liquid chromatographic determination of bilirubin distribution on serum proteins. Clin Chim Acta 1991; 201:35-43. [PMID: 1724214 DOI: 10.1016/0009-8981(91)90022-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We describe a high-performance liquid chromatographic method for the determination of bilirubin distribution on serum proteins. The procedure is based on both size-exclusion and adsorptive properties of the column packing material LiChrosorb Diol. The elution of all sample constituents is accomplished by means of an aqueous mobile phase containing phosphate buffered solution of adult serum, supplemented by a small amount of bilirubin. The different distribution of bilirubin on albumin, beta-lipoprotein, and as free (loosely bound) pigment fraction is exemplified by assaying normal adult and infant sera.
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Affiliation(s)
- L Soltés
- Institute of Experimental Pharmacology, Slovak Academy of Sciences, Bratislava, Czechoslovakia
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20
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Fang LS, Bada JL. The blue-green blood plasma of marine fish. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. B, COMPARATIVE BIOCHEMISTRY 1990; 97:37-45. [PMID: 2253479 DOI: 10.1016/0305-0491(90)90174-r] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
1. The blue-green coloration of the blood plasma in some marine fishes, which is attributed to a protein bound tetrapyrrol (biliverdin), is an anomaly in vertebrates. 2. Recent studies have shown that biliverdin not only occurs in many fish, but is also present in the blood of tobacco hornworm, the wings of moth and butterfly, the shell of bird eggs, the serum and egg of frog, the placenta of dog and in the blood of humans suffering from hepatic diseases. 3. In this review, we begin with a historical account of the description of the presence of blue-green blood plasma in fish, and then consider the biochemistry, metabolism, physiology, and the ecological implications of biliverdin in fish. 4. A comparative description of the occurrence of biliverdin in fish and other animals is presented. 5. The mechanism of accumulation of biliverdin in fish blood and its evolutionary significance are also considered. It is suggested that this process may serve as a useful model for further research on bile pigment metabolism in other animals.
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Affiliation(s)
- L S Fang
- Department of Marine Resources, National Sun-Yat Sen University, Kaohsing, Taiwan, Republic of China
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21
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Understanding bilirubin conformation and binding. Circular dichroism of human serum albumin complexes with bilirubin and its esters. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)37442-8] [Citation(s) in RCA: 89] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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22
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Million CJP, Klibanov AM, Langer R. Kinetics of bilirubin oxidase and modeling of an immobilized bilirubin oxidase reactor for bilirubin detoxification. Biotechnol Bioeng 1988; 31:536-46. [DOI: 10.1002/bit.260310605] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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23
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Abstract
Bilirubin, when bound to human albumin and at concentrations present in normal human plasma, protects albumin-bound linoleic acid from peroxyl radical-induced oxidation in vitro. Initially, albumin-bound bilirubin (Alb-BR) is oxidized at the same rate as peroxyl radicals are formed and biliverdin is produced stoichiometrically as the oxidation product. On an equimolar basis, Alb-BR successfully competes with uric acid for peroxyl radicals but is less efficient in scavenging these radicals than vitamin C. These results show that 1 mol of Alb-BR can scavenge 2 mol of peroxyl radicals and that small amounts of plasma bilirubin are sufficient to prevent oxidation of albumin-bound fatty acids as well as of the protein itself. The data indicate a role for Alb-BR as a physiological antioxidant in plasma and the extravascular space.
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24
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Sung C, Lavin A, Klibanov AM, Langer R. An immobilized enzyme reactor for the detoxification of bilirubin. Biotechnol Bioeng 1986; 28:1531-9. [DOI: 10.1002/bit.260281011] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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25
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Fang LS, Ong CW, Hwang WS. A comparative study on the binding characteristics of the tight serum biliverdin-protein complexes in two fishes: Anguilla japonica and Clinocottus analis. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. B, COMPARATIVE BIOCHEMISTRY 1986; 84:393-6. [PMID: 3743032 DOI: 10.1016/0305-0491(86)90096-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The binding characteristics of biliverdin to its carrier protein in the blue-green blood of Clinocottus analis (woolly sculpin) and Anguilla japonica (freshwater eel) were operationally defined by various chemical probing methods and spectra analysis. The biliverdin in C. analis is a rotatable coiled molecule enveloped in a hydrophobic pocket of its carrier protein. The biliverdin in A. japonica is an open form molecule with external hydrogen bond or weak ester bond interacting with the carrier protein. This, for the first time, shows that the novel firm binding biliprotein complexes in the blood of different species are biochemically different. Their comparative and evolutionary significance is discussed.
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26
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Lorey FW, Smith DG, Ahlfors CE. Bilirubin binding by the fractionated alternate allelic components of heterozygous monkey albumin. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 1985; 68:169-71. [PMID: 4061607 DOI: 10.1002/ajpa.1330680204] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Analysis of bilirubin-binding parameters for purified albumin of nine rhesus monkeys heterozygous for albumin MacA and albumin MacB was performed after separating these two albumin forms by fast protein liquid chromatography (FPLC). The binding capacity (n) for MacA-enriched samples was lower than that for the MacB variant in eight of nine fraction pairs analyzed, while the affinity constant (K) was higher in all nine MacA-enriched samples. The values for n X K were higher in MacA-enriched samples in eight of nine pairs tested. These data, together with previous studies, geographic specificity of the MacB variant, and the presence of dietary competitors for the primary bilirubin binding site on the albumin molecule, suggest an evolutionary advantage for the MacB variant only in areas where the dietary competitors are present.
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27
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Trueba M, Vallejo A, Zaton A, Abad C. Preferential solvation of bovine serum albumin in cobalt nitrate solutions. Inorganica Chim Acta 1985. [DOI: 10.1016/s0020-1693(00)82286-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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28
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Fang LS. Study on a special binding phenomenon of biliverdin in the blood of the eel, Anguilla japonica. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. B, COMPARATIVE BIOCHEMISTRY 1985; 81:723-6. [PMID: 4028686 DOI: 10.1016/0305-0491(85)90394-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Biliverdin is bound firmly with a plasma protein in the blood of the eel, Anguilla japonica. The firm binding, although likely noncovalent, could be formed only in vivo under the experimental conditions. Characterization of the carrier protein indicated that it is a serum albumin. A similar phenomenon is not detectable in ten other fish species examined in this study.
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29
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Abstract
The accurate determination of the types and amounts of bilirubin species in serum is important for diagnostic purposes as well as for therapeutic monitoring. However, of the determinations routinely performed in the clinical laboratory, those for bilirubins are not among the more accurate and exhibit significant method variability. In this review, the structural, stability, solubility, and albumin-binding properties of serum bilirubins are discussed with respect to their impact on analytical methods. Following a consideration of analytical standards, methods for the determination of unconjugated and conjugated bilirubins are reviewed and recent developments are evaluated. Finally, the present capabilities and future potential of the methods for producing information applicable to the development of new or improved methods of determination are summarized.
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30
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Abstract
Photobilirubin II, a stereoisomer of bilirubin, binds to human serum albumin at a single binding site (K = 2.2 x 10(6)M-1), presumably the high-affinity bilirubin-binding site. Binding in the secondary (class II) binding sites is of minor importance. The results are discussed with respect to photometabolism of bilirubin and as a possible source of error in the determination of bilirubin unbound to albumin.
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31
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Ahlfors CE, Shwer ML, Wennberg RP. Absence of bilirubin binding competitors during phototherapy for neonatal jaundice. Early Hum Dev 1982; 6:125-30. [PMID: 7094850 DOI: 10.1016/0378-3782(82)90099-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Bilirubin-albumin binding was quantitated (peroxidase method) before, during, and after phototherapy in 21 jaundiced infants. Binding was analyzed at two different serum dilutions (1:1.8 and 1:57) to determine whether binding competitors are present during phototherapy. No significant changes in binding were found at either dilution during phototherapy, regardless of birthweight, gestational age, or illness. Serum binding of bilirubin does not appear to be altered during phototherapy.
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