Biosynthesis of food constituents: Vitamins. 2. Water-soluble vitamins: Part 2 - a review

Velı́šek, J.; Cejpek, Karel

doi:10.17221/744-cjfs

Cited by 6 publications

(7 citation statements)

References 23 publications

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“…These enzymes include sugar‐1,4‐lactone oxidases, one of which is d‐ arabanose‐1,4‐lactone oxidase, the enzyme that catalyzes the final step in the biosynthesis of d‐ erythroascorbate, an antioxidant made by fungi and actinobacteria. Homologous to d‐ arabinose‐1,4‐lactone oxidase is l‐ gulonolactone oxidase which converts l‐ gulonolactone to l‐ xylo‐hex‐2‐ulono‐1,4‐lactone, the precursor of ascorbate [45]. Among the actinobacteria that have this gene arrangement are Catenulispora acidiphila , Streptomyces griseus , Streptomyces coelicolor , Thermobispora bispora , Streptosporangium roseum and Thermomonospora curvata .…”

Section: Resultsmentioning

confidence: 99%

The major facilitator superfamily (MFS) revisited

et al. 2012

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The major facilitator superfamily (MFS) is the largest known superfamily of secondary carriers found in the biosphere. It is ubiquitously distributed throughout virtually all currently recognized organismal phyla. This superfamily currently (2012) consists of 74 families, each of which is usually concerned with the transport of a certain type of substrate. Many of these families, defined phylogenetically, do not include even a single member that is functionally characterized. In this article, we probe the evolutionary origins of these transporters, providing evidence that they arose from a single 2‐transmembrane segment (TMS) hairpin structure that triplicated to give a 6‐TMS unit that duplicated to a 12‐TMS protein, the most frequent topological type of these permeases. We globally examine MFS protein topologies, focusing on exceptional proteins that deviate from the norm. Nine distantly related families appear to have members with 14 TMSs in which the extra two are usually centrally localized between the two 6‐TMS repeat units. They probably have arisen by intragenic duplication of an adjacent hairpin. This alternative topology probably arose multiple times during MFS evolution. Convincing evidence for MFS permeases with fewer than 12 TMSs was not forthcoming, leading to the suggestion that all 12 TMSs are required for optimal function. Some homologs appear to have 13, 14, 15 or 16 TMSs, and the probable locations of the extra TMSs were identified. A few MFS permeases are fused to other functional domains or are fully duplicated to give 24‐TMS proteins with dual functions. Finally, the MFS families with no known function were subjected to genomic context analyses leading to functional predictions.

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Section: Resultsmentioning

confidence: 99%

The major facilitator superfamily (MFS) revisited

et al. 2012

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“…15 Unlike other vitamins that are synthesized primarily in plants, cobalamins are produced only by microbial synthesis. [15][16][17] The cobalamins from the microbial flora in the gastrointestinal system of ruminants are absorbed and stored in their tissues; from there, they are passed on to other animals in the food chain. 15 So liver, kidney, muscle tissue, milk and eggs are abundant sources of cobalamins.…”

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confidence: 99%

“…[15][16][17] The cobalamins from the microbial flora in the gastrointestinal system of ruminants are absorbed and stored in their tissues; from there, they are passed on to other animals in the food chain. 15 So liver, kidney, muscle tissue, milk and eggs are abundant sources of cobalamins. 1 The stability of vitamin B12 is dependent on a number of conditions: it is fairly stable at pH 4-6, even at high temperature; in alkaline media or in the presence of reducing agents such as ascorbic acid this vitamin is destroyed to a great extent.…”

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confidence: 99%

“…The most important cobalamins are cyanocobalamin, hydroxycobalamin, 5′‐deoxyadenosylcobalamin (coenzyme B12) and methylcobalamin. In a more specific way, the term vitamin B12 is used to refer to cyanocobalamin only; due to its stability, it is the principal form used in fortified food and pharmaceutical formulations 15. Unlike other vitamins that are synthesized primarily in plants, cobalamins are produced only by microbial synthesis 15–17.…”

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confidence: 99%

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Simultaneous determination of water‐soluble vitamins in selected food matrices by liquid chromatography/electrospray ionization tandem mass spectrometry

Gentili

Caretti

D’Ascenzo

et al. 2008

Rapid Comm Mass Spectrometry

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A rapid, simple and sensitive method based on liquid chromatography/tandem mass spectrometry (LC/MS/MS) with an electrospray ionization (ESI) source for the simultaneous analysis of fourteen water-soluble vitamins (B1, B2, two B3 vitamers, B5, five B6 vitamers, B8, B9, B12 and C) in various food matrices, i.e. maize flour, green and golden kiwi and tomato pulp, is presented here. Analytes were separated by ion-suppression reversed-phase liquid chromatography in less than 10 min and detected in positive ion mode. Sensitivity and specificity of this method allowed two important results to be achieved: (i) limits of detection of the analytes at ng g(-1) levels (except for vitamin C); (ii) development of a rapid sample treatment that minimizes analyte exposition to light, air and heat, eliminating any step of extract concentration. Analyte recovery depended on the type of matrix. In particular, recovery of the analytes in maize flour was > or =70%, with the exception of vitamin C, pyridoxal-5'-phosphate and vitamin B9 (ca 40%); with tomato pulp, recovery was > or =64%, except for vitamin C (41%); with kiwi, recovery was > or =73%, except for nicotinamide (ca. 30%).

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“…Using pyridoxamine 5'-phosphate as a cofactor, glutamate 1-semialdehyde 2,1-aminomutase (glutamate semialdehyde aminotransferase, EC 5.4.3.8) converts glutamic acid 1-semialdehyde to 5-aminolevulinic acid via 4,5-diaminopentanoic acid (IUBMB 2007 The next three steps of porphyrin biosynthesis follow those of vitamin B 12 coenzyme (adenosylcobalamin) pathway. These steps (Figure 4) start with the condensation of two 5-aminolevulinic acids to form porphobilinogen (aminolevulinate dehydratase or porphobilinogen synthase, EC 4.2.1.24), four porphobilinogens are converted to hydroxymethylbilane (hydroxymethylbilane synthase, EC 2.5.1.61), which is subsequently transformed to uroporphyrinogen III also known as urogen III (uroporphyrinogen-III synthase, EC 4.2.1.75), the common intermediate in the biosynthesis of corrinoids and porphyrins (KEGG 2007;Velíšek & Cejpek 2007b). …”

Section: Porphyrinsmentioning

confidence: 99%