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Hu ZQ, Li X, Liu LX, Yu CB, Zhou YG. Ruthenium-Catalyzed Asymmetric Transfer Hydrogenation of β-Substituted α-Oxobutyrolactones. J Org Chem 2021; 86:17453-17461. [PMID: 34730976 DOI: 10.1021/acs.joc.1c02156] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
A concise and effective ruthenium-catalyzed asymmetric transfer hydrogenation of β-substituted α-oxobutyrolactones has been developed, delivering a series of cis-β-substituted α-hydroxybutyrolactone derivatives with excellent yields, enantioselectivities, and diastereoselectivities. Two consecutive stereogenic centers were constructed in one step through dynamic kinetic resolution under basic conditions. The reaction could be conducted on a gram scale without loss of activity and enantioselectivity. The reductive products could be easily transformed into useful building blocks.
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Affiliation(s)
- Zi-Qi Hu
- Zhang Dayu School of Chemistry, Dalian University of Technology, 2 Linggong Road, Dalian 116024, P. R. China
| | | | | | | | - Yong-Gui Zhou
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, P. R. China
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Chanda D, Venkataswamy GM, Hipparagi LV, Harohally NV. Critical role of Bronsted acid in Lewis-acid-catalyzed synthesis of Amadori and Heyns compounds of β-amino acids. SYNTHETIC COMMUN 2021. [DOI: 10.1080/00397911.2021.1971718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Debasree Chanda
- Spice and Flavour Science, CSIR-CFTRI, Mysuru, Karnataka, India
- Academy of Scientific and Innovative Research, Ghaziabad, India
| | - Gangothri M. Venkataswamy
- Spice and Flavour Science, CSIR-CFTRI, Mysuru, Karnataka, India
- Academy of Scientific and Innovative Research, Ghaziabad, India
| | - Lagamawwa V. Hipparagi
- Spice and Flavour Science, CSIR-CFTRI, Mysuru, Karnataka, India
- Academy of Scientific and Innovative Research, Ghaziabad, India
| | - Nanishankar V. Harohally
- Spice and Flavour Science, CSIR-CFTRI, Mysuru, Karnataka, India
- Academy of Scientific and Innovative Research, Ghaziabad, India
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Egelandsdal B, Oostindjer M, Hovland EM, Okholm B, Saarem K, Bjerke F, Ruud L, Grabež V, Haug A. Identifying labelling and marketing advantages of nutrients in minced beef meat: A case study. Meat Sci 2019; 159:107920. [PMID: 31473367 DOI: 10.1016/j.meatsci.2019.107920] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 06/24/2019] [Accepted: 08/20/2019] [Indexed: 11/29/2022]
Abstract
In 2006, the European Commission approved nutrition and health claim regulations of foods to stimulate healthier choices. To document how commercial, minced beef meat complied with regulations, meat samples from 72 carcasses were analysed. These samples were a source of niacin (B3), pyridoxine (B6), phosphorus and iron (cow meat only), and a rich source of protein, monounsaturated fat, vitamin B12 and zinc. A potential exists for establishing beef meat as a source of vitamin K, iron and selenium. The meat's nutrient relevance for young women when ingesting 150 g of raw beef mince/day was estimated. Increased levels of riboflavin (B2), pantothenic acid (B5), iron and selenium beyond presently observed, would better support this group's recommended nutrient intake. If the bioactivity of 25-OH-vitamin D3 could be used in calculations, vitamin D3 in the minced meat would add positively to the intake of vitamin D3 that was 49% of the recommended intake.
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Affiliation(s)
- Bjørg Egelandsdal
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, P.O. Box 5003, NO-1432 Aas, Norway.
| | - Marije Oostindjer
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, P.O. Box 5003, NO-1432 Aas, Norway
| | - Ellen-Margrethe Hovland
- Animalia - the Norwegian Meat and Poultry Research Centre, P.O. Box 396 Økern, NO-0513 Oslo, Norway
| | - Bolette Okholm
- Ministry of Environment and Food of Denmark, The Danish Veterinary and Food Administration, Laboratory Aarhus, Sønderskovvej 5, 8520 Lystrup, Denmark
| | | | - Frøydis Bjerke
- Animalia - the Norwegian Meat and Poultry Research Centre, P.O. Box 396 Økern, NO-0513 Oslo, Norway
| | - Lene Ruud
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, P.O. Box 5003, NO-1432 Aas, Norway
| | - Vladana Grabež
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, P.O. Box 5003, NO-1432 Aas, Norway
| | - Anna Haug
- Faculty of Biosciences, Norwegian University of Life Sciences, P.O. Box 5003, NO-1432 Aas, Norway
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Micronutrient status assessment in humans: Current methods of analysis and future trends. Trends Analyt Chem 2018. [DOI: 10.1016/j.trac.2018.02.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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5
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Assessment of bioavailable B vitamin content in food using in vitro digestibility assay and LC-MS SIDA. Anal Bioanal Chem 2017; 409:6475-6484. [DOI: 10.1007/s00216-017-0592-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 08/14/2017] [Accepted: 08/17/2017] [Indexed: 10/18/2022]
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Khaksari M, Mazzoleni LR, Ruan C, Kennedy RT, Minerick AR. Data representing two separate LC-MS methods for detection and quantification of water-soluble and fat-soluble vitamins in tears and blood serum. Data Brief 2017; 11:316-330. [PMID: 28275666 PMCID: PMC5328915 DOI: 10.1016/j.dib.2017.02.033] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 01/09/2017] [Accepted: 02/13/2017] [Indexed: 11/18/2022] Open
Abstract
Two separate liquid chromatography (LC)-mass spectrometry (MS) methods were developed for determination and quantification of water-soluble and fat-soluble vitamins in human tear and blood serum samples. The water-soluble vitamin method was originally developed to detect vitamins B1, B2, B3 (nicotinamide), B5, B6 (pyridoxine), B7, B9 and B12 while the fat-soluble vitamin method detected vitamins A, D3, 25(OH)D3, E and K1. These methods were then validated with tear and blood serum samples. In this data in brief article, we provide details on the two LC-MS methods development, methods sensitivity, as well as precision and accuracy for determination of vitamins in human tears and blood serum. These methods were then used to determine the vitamin concentrations in infant and parent samples under a clinical study which were reported in "Determination of Water-Soluble and Fat-Soluble Vitamins in Tears and Blood Serum of Infants and Parents by Liquid Chromatography/Mass Spectrometry DOI:10.1016/j.exer.2016.12.007 [1]". This article provides more details on comparison of vitamin concentrations in the samples with the ranges reported in the literature along with the medically accepted normal ranges. The details on concentrations below the limits of detection (LOD) and limits of quantification (LOQ) are also discussed. Vitamin concentrations were also compared and cross-correlated with clinical data and nutritional information. Significant differences and strongly correlated data were reported in [1]. This article provides comprehensive details on the data with slight differences or slight correlations.
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Affiliation(s)
- Maryam Khaksari
- Department of Chemical Engineering, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931, USA
| | - Lynn R Mazzoleni
- Department of Chemistry, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931, USA
| | - Chunhai Ruan
- Metabolomics Core, BRCF, University of Michigan, 500 South State Street, Ann Arbor, MI 48109, USA
| | - Robert T Kennedy
- Department of Chemistry, University of Michigan, 500 South State Street, Ann Arbor, MI, 48109, USA
| | - Adrienne R Minerick
- Department of Chemical Engineering, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931, USA
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Khaksari M, Mazzoleni LR, Ruan C, Kennedy RT, Minerick AR. Determination of water-soluble and fat-soluble vitamins in tears and blood serum of infants and parents by liquid chromatography/mass spectrometry. Exp Eye Res 2017; 155:54-63. [DOI: 10.1016/j.exer.2016.12.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 12/15/2016] [Accepted: 12/16/2016] [Indexed: 11/24/2022]
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Hälvin K, Nisamedtinov I, Paalme T. Comparison of different extraction methods to determine free and bound forms of B-group vitamins in quinoa. Anal Bioanal Chem 2014; 406:7355-66. [DOI: 10.1007/s00216-014-8122-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Revised: 08/15/2014] [Accepted: 08/19/2014] [Indexed: 11/30/2022]
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Production of a monoclonal antibody and its application in an optical biosensor based assay for the quantitative measurement of pantothenic acid (vitamin B5) in foodstuffs. Food Chem 2012. [DOI: 10.1016/j.foodchem.2012.02.116] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Rychlik M, Asam S. Stabilisotopenverdünnungsanalysen zur Quantifizierung organischer Spurenkomponenten in der Lebensmittelanalytik. ACTA ACUST UNITED AC 2009. [DOI: 10.1007/s12302-009-0082-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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11
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Vitamins. Food Chem 2008. [DOI: 10.1007/978-3-540-69934-7_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Chakauya E, Coxon KM, Wei M, Macdonald MV, Barsby T, Abell C, Smith AG. Towards engineering increased pantothenate (vitamin B(5)) levels in plants. PLANT MOLECULAR BIOLOGY 2008; 68:493-503. [PMID: 18726075 DOI: 10.1007/s11103-008-9386-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2008] [Accepted: 07/31/2008] [Indexed: 05/26/2023]
Abstract
Pantothenate (vitamin B(5)) is the precursor of the 4'-phosphopantetheine moiety of coenzyme A and acyl-carrier protein. It is made by plants and microorganisms de novo, but is a dietary requirement for animals. The pantothenate biosynthetic pathway is well-established in bacteria, comprising four enzymic reactions catalysed by ketopantoate hydroxymethyltransferase (KPHMT), L: -aspartate-alpha-decarboxylase (ADC), pantothenate synthetase (PS) and ketopantoate reductase (KPR) encoded by panB, panD, panC and panE genes, respectively. In higher plants, the genes encoding the first (KPHMT) and last (PS) enzymes have been identified and characterised in several plant species. Commercially, pantothenate is chemically synthesised and used in vitamin supplements, feed additives and cosmetics. Biotransformation is an attractive alternative production system that would circumvent the expensive procedures of separating racemic intermediates. We explored the possibility of manipulating pantothenate biosynthesis in plants. Transgenic oilseed rape (Brassica napus) lines were generated in which the E. coli KPHMT and PS genes were expressed under a strong constitutive CaMV35SS promoter. No significant change of pantothenate levels in PS transgenic lines was observed. In contrast plants expressing KPHMT had elevated pantothenate levels in leaves, flowers siliques and seed in the range of 1.5-2.5 fold increase compared to the wild type plant. Seeds contained the highest vitamin content, indicating that they might be the ideal target for production purposes.
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Affiliation(s)
- Ereck Chakauya
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK.
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Gutzeit D, Klaubert B, Rychlik M, Winterhalter P, Jerz G. Effects of processing and of storage on the stability of pantothenic acid in sea buckthorn products (Hippophaë rhamnoides L. ssp. rhamnoides) assessed by stable isotope dilution assay. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2007; 55:3978-84. [PMID: 17447792 DOI: 10.1021/jf070223+] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
A stable isotope dilution assay for quantification of pantothenic acid in sea buckthorn berries, juice, and concentrate using a four-fold labeled isotopologue of vitamin B5 as the internal standard was adopted using reversed phase liquid chromatography-mass spectrometry with electrospray ionization. Because of a rapid sample clean up procedure without the necessity of external calibration, this methodology permits the accurate analysis of a high number of samples within a short time. Sea buckthorn juice was stored at 25 and 40 degrees C for up to 7 days to determine the effects of storage temperature on the stability of pantothenic acid. Analysis of kinetic data suggested that the degradation follows a first-order model. The results of the experiments showed that storage of sea buckthorn juice for 7 days at ambient temperature (25 degrees C) already resulted in a significant degradation of pantothenic acid of about 18%. The processing effects of juice production and subsequent concentration revealed a decrease of about 6-7% in the juice and of 23% in the juice concentrate.
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Affiliation(s)
- Derek Gutzeit
- Central Institute of the Bundeswehr Medical Service Munich, Ingolstädter Landstrasse 102, 85748 Garching, Hochbrück, Germany
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Schlatterer J, Maurer S, Breithaupt DE. Quantification of 3R,3′R-zeaxanthin in plant derived food by a diastereomeric dilution assay applying chiral high-performance liquid chromatography. J Chromatogr A 2006; 1137:216-22. [PMID: 17070819 DOI: 10.1016/j.chroma.2006.10.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2006] [Revised: 10/06/2006] [Accepted: 10/11/2006] [Indexed: 10/24/2022]
Abstract
For quantification of 3R,3'R-zeaxanthin in plant derived food, a new diastereomeric dilution assay (DIDA) was developed using chiral high-performance liquid chromatography coupled to diode-array detection (HPLC/DAD). As diastereomeric internal standard (I.S.), 3R,3'S-(meso)-zeaxanthin was applied. DIDA showed sufficient sensitivity with low limits of detection and quantification (18 microg100 g(-1) and 45 microg 100 g(-1)), a good inter-assay coefficient of variation (2.4%), determined by analysis of a certified BCR reference material, and a good recovery (94.7%). To prove the applicability of DIDA, various plant materials were analyzed, showing that DIDA is highly advisable if saponification is applied during work-up to hydrolyze xanthophyll esters.
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Affiliation(s)
- Jörg Schlatterer
- University of Hohenheim, Institute of Food Chemistry, Garbenstrasse 28, 70599 Stuttgart, Germany
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Rychlik M, Mayr A. Quantitation of N2-[1-(1-carboxy)ethyl]folic acid, a nonenzymatic glycation product of folic acid, in fortified foods and model cookies by a Stable isotope dilution assay. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2005; 53:5116-24. [PMID: 15969484 DOI: 10.1021/jf0503311] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
A stable isotope dilution assay (SIDA) for the quantitation of N(2)-[1-(carboxy)ethyl]folic acid (CEF) has been developed by using [(2)H(4)]CEF as the internal standard. After sample cleanup by anion exchange chromatography, the three-dimensional specifity of liquid chromatography-tandem mass spectrometry enabled unequivocal determination of the nonenzymatic glycation product of folic acid (FA). When CEF was added to cornstarch, the detection limit for CEF was found to be 0.4 microg/100 g, and a recovery of 98.5% was determined. In analyses of cookies, the intra-assay coefficient of variation was 8.0% (n = 5). Application of the SIDA to commercial cookies produced from wheat flour fortified with FA revealed CEF contents of up to 7.1 microg/100 g, which accounted for approximately 10-20% of the cookies' FA content. In baby foods, multivitamin juices, and multivitamin sweets, however, CEF was not detectable. Further studies on CEF formation during baking of cookies made from fortified flour and different carbohydrates revealed that fructose was most effective in generating CEF followed by glucose, lactose, and sucrose with 12.5, 3.9, 2.5, and 2.5 microg/100 g of dry mass, respectively. During baking, approximately 50% of FA was retained for both monosaccharides fructose and glucose, and 77% as well as 85% of its initial content was retained for the disaccharides lactose and sucrose, respectively. Of the degraded amount of FA, CEF comprised 28% for fructose as well as 18, 12, and 8% for sucrose, lactose, and glucose, respectively. Therefore, CEF can be considered an important degradation product of FA in baked foods made from fructose. To retain a maximum amount of FA, products should rather be baked with sucrose than with reducing carbohydrates.
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Affiliation(s)
- Michael Rychlik
- Lehrstuhl für Lebensmittelchemie der Technischen Universität München, Garching, Germany.
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Lindenmeier M, Schieberle P, Rychlik M. Quantification of ochratoxin A in foods by a stable isotope dilution assay using high-performance liquid chromatography-tandem mass spectrometry. J Chromatogr A 2004; 1023:57-66. [PMID: 14760850 DOI: 10.1016/j.chroma.2003.10.004] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A stable isotope dilution assay (SIDA) was developed for quantification of the mycotoxin ochratoxin A (OTA) by using [2H5]-OTA as internal standard. The synthesis of labelled OTA was accomplished by acid hydrolysis of unlabelled OTA and subsequent coupling one of the products, ochratoxin alpha, to [2H5]-L-phenylalanine. The mycotoxin was quantified in foods by LC-tandem MS after extraction with buffers containing [2H5]-OTA and clean-up by immuno affinity chromatography or by solid phase extraction on silica. The method showed a sufficient sensitivity with a low detection and quantification limit of 0.5 and 1.4 microg/kg, respectively, and good precision in inter-assay studies showing a CV (n = 3) of 3.6%. The analysis of certified reference materials resulted in a low bias of 2.1% from the certified values and revealed excellent accuracy of the new method. To prove the suitability of SIDA. OTA was quantified in a number of food samples and resulted mainly in not detectable OTA contents. However, three samples of raisins exceeded the legal limit of 10 microg/kg and highlighted the need for further controlling the contamination with the mycotoxin.
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Affiliation(s)
- Michael Lindenmeier
- Institut für Lebensmittelchemie der Technischen Universität München, Lichtenbergstr. 4, D-85748 Garching, Germany
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Pakin C, Bergaentzlé M, Hubscher V, Aoudé-Werner D, Hasselmann C. Fluorimetric determination of pantothenic acid in foods by liquid chromatography with post-column derivatization. J Chromatogr A 2004; 1035:87-95. [PMID: 15117078 DOI: 10.1016/j.chroma.2004.02.042] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A method to determine the content of free pantothenic acid in various foods by reverse phase liquid chromatography-fluorimetry is reported. It includes a purification of the samples by successive passages through anion and cation exchange cartridges and a post-column derivatization of pantothenic acid as the fluorescent 1-alkylthio-2-alkylisoindole (reaction of beta-alanin, formed by hot alkaline hydrolysis of pantothenic acid, with orthophthaldialdehyde in the presence of 3-mercaptopropionic acid). An enzymatic hydrolysis prior to the purification step (pepsin at 50 degrees C for 3 h, then pantetheinase and alkaline phosphatase at 20 degrees C for 18 h) made it possible to release the bound pantothenic acid and thus to obtain the total Vitamin B5 content of these foodstuffs. The method proposed for the determination of free and bound pantothenic acid gives a good recovery rate (96-101%) and a satisfactory repeatability (R.S.D.r less than 8%). Owing to its low detection limit (0.65 microg g(-1)) and the good resolution of the pantothenic acid peak, it could most probably be applied to the determination of this vitamin in any foodstuff.
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Affiliation(s)
- C Pakin
- Laboratoire de Chimie Analytique et Sciences de l'Alimient (UMR 7512), Faculté de Pharmacie, 74 route du Rhin, 67400 Illkirch, France
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Rychlik M. Simultaneous analysis of folic acid and pantothenic acid in foods enriched with vitamins by stable isotope dilution assays. Anal Chim Acta 2003. [DOI: 10.1016/j.aca.2003.08.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Abstract
Biotin is an essential micronutrient for normal cellular function, growth, and development. Biotin deficiency leads to pathologic, dermatologic, and neurocutaneous manifestations in skin and its appendages. Previous studies described the presence of specific biotin transport systems in the epithelia of the intestine, liver, kidney, and placenta, and in blood mononuclear cells. The aim of this study was to examine biotin transport into human keratinocytes. Uptake of [3H]biotin was measured both in the HaCaT cell line and in native keratinocytes in primary culture. Uptake of [3H]biotin (6 nM) in HaCaT cells was linear for up to 5 min of incubation. In the presence of an Na+ gradient total biotin uptake was 4- to 5-fold higher than in the absence of sodium ions. Biotin uptake was not altered by H+ and Cl- gradients. This transport system exhibited a Michaelis-Menten constant for biotin of 22.7+/-1.0 microM and a maximal velocity of 163.6+/-3.5 pmol per 5 min per mg protein. [3H]Biotin uptake (6 nM) was strongly inhibited by lipoic acid (oxidized form, Ki=4.6 microM; reduced form, Ki=11.4 microM), pantothenic acid (Ki=1.2 microM), and desthiobiotin (Ki=15.2 microM), but not by biocytin or biotin methyl ester. Measured at [3H]biotin concentrations of 0.1-10 nM we obtained kinetic evidence for the presence of a second transport component that is saturable at very low biotin concentrations (Kt=2.6+/-0.1 nM). Unlabeled lipoic acid and pantothenic acid (20 nM) did not inhibit the [3H]biotin uptake (1 nM). We conclude that human keratinocytes express the Na+-dependent multivitamin transporter with preference for pantothenate and a very high affinity transport component with specificity for biotin.
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Affiliation(s)
- Franziska Grafe
- Biozentrum of the Martin-Luther-University, Membrane Transport Group, Institute of Pharmaceutics and Biopharmaceutics, Martin-Luther-University Halle-Wittenberg, Halle, Germany
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Freisleben A, Schieberle P, Rychlik M. Syntheses of labeled vitamers of folic acid to be used as internal standards in stable isotope dilution assays. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2002; 50:4760-4768. [PMID: 12166957 DOI: 10.1021/jf025571k] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
[2H4]Folic acid was synthesized by deuterating p-aminobenzoic acid, which was then coupled to glutamic acid and 6-formylpterin. Using [2H4]folic acid as starting component enabled the preparation of labeled vitamers tetrahydrofolate, 5-formyltetrahydrofolate, 5-methyltetrahydrofolate, and 10-formylfolate which were characterized by electrospray mass spectrometry and collision-induced dissociation. The mass spectrometric studies confirmed that the compounds could be used as internal standards in stable isotope dilution assays.
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Affiliation(s)
- Achim Freisleben
- Institut für Lebensmittelchemie der Technischen Universität München, Lichtenbergstrasse 4, D-85748 Garching, Germany
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Rychlik M. Mass spectrometric studies of trimethylsilylpantothenic acid and related substances. JOURNAL OF MASS SPECTROMETRY : JMS 2001; 36:555-562. [PMID: 11391812 DOI: 10.1002/jms.157] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The characteristic fragment of trimethylsilylated pantothenic acid (TMS-PA) at m/z 291 upon electron ionization was shown to originate from the molecular ion by a McLafferty rearrangement instead of by ejection of 1,1,3,3-tetramethyl-1,3-disilacyclobutane. The verification consisted of labelling experiments and high-resolution mass spectrometry of the fragment and studies on its isotopic distribution. The remaining fragmentation pathways of TMS-PA were clarified by B/E-linked scans and collision-induced dissociation.
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Affiliation(s)
- M Rychlik
- Institut für Lebensmittelchemie der Technischen Universität München, Lichtenbergstr. 4, D-85748 Garching, Germany.
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Rychlik M, Bosset JO. Flavour and off-flavour compounds of Swiss Gruyère cheese. Identification of key odorants by quantitative instrumental and sensory studies. Int Dairy J 2001. [DOI: 10.1016/s0958-6946(01)00109-1] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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