Vitamin C

@article{Linster2007VitaminC,
  title={Vitamin C},
  author={Carole L Linster and Emile Van Schaftingen},
  journal={The FEBS Journal},
  year={2007},
  volume={274}
}
Vitamin C, a reducing agent and antioxidant, is a cofactor in reactions catalyzed by Cu+‐dependent monooxygenases and Fe2+‐dependent dioxygenases. It is synthesized, in vertebrates having this capacity, from d‐glucuronate. The latter is formed through direct hydrolysis of uridine diphosphate (UDP)‐glucuronate by enzyme(s) bound to the endoplasmic reticulum membrane, sharing many properties with, and most likely identical to, UDP‐glucuronosyltransferases. Non‐glucuronidable xenobiotics… Expand
An Overview of the Characteristics and Function of Vitamin C in Various Tissues: Relying on its Antioxidant Function
TLDR
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The Myo‐inositol pathway does not contribute to ascorbic acid synthesis
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Radiotracer experiments with 3H‐myo‐inositol revealed that the mutants in glucuronokinase1 accumulate only glucuronic acid and incorporate less metabolite into cell wall polymers, suggesting that Arabidopsis cannot efficiently use glucURonic acid for AsA biosynthesis. Expand
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  • 2021
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The terminal step in vitamin C biosynthesis in Trypanosoma cruzi is mediated by a FMN-dependent galactonolactone oxidase.
TLDR
FMN is an essential cofactor for enzyme activity and binds to TcGAL non-covalently, and a histidine residue located within the N-terminal flavin-binding motif has been shown to be crucial for cofactor binding. Expand
Ascorbic acid metabolism and functions: A comparison of plants and mammals
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  • Free radical biology & medicine
  • 2018
TLDR
Ascorbate status influences gene expression in plants and mammals but at present there is little evidence that it acts as a specific signalling molecule and the possibility that dehydroascorbylation is a regulatory post‐translational protein modification could be explored. Expand
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The increasing knowledge of the functions of ascorbate and of its molecular sites of action can mechanistically substantiate a place for asCorbate in the treatment of various diseases. Expand
Vitamin C in Plants: From Functions to Biofortification
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In this review, the multiple roles of vitamin C in plant physiology as well as the regulation of its content, through biosynthetic or recycling pathways, are analyzed and attention is paid to the strategies that have been used to increase the content of vitamins C in crops. Expand
Vitamin C: the known and the unknown and Goldilocks.
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Glucuronate, the precursor of vitamin C, is directly formed from UDP‐glucuronate in liver
TLDR
The sensitivity of UDP‐glucuronidase to metyrapone and other stimulatory xenobiotics was lost in washed microsomes, even in the presence of ATP‐Mg, but it could be restored by adding a heated liver high‐speed supernatant or CoASH. Expand
L-ascorbic acid biosynthesis.
TLDR
Assessment of the literature reveals that little is known about many of the enzymes involved in ascorbate biosynthesis or about the factors controlling flux through the pathways. Expand
Vitamin C transport systems of mammalian cells
TLDR
Two isoforms of vitamin C transport proteins, SVCT1 and SVCT2, have recently been cloned from humans and rats and are predicted to have 12 transmembrane domains, but they share no structural homology with other Na+ co-transporters. Expand
Rapid Stimulation of Free Glucuronate Formation by Non-glucuronidable Xenobiotics in Isolated Rat Hepatocytes*
TLDR
It is concluded that the stimulation of vitamin C synthesis exerted by some xenobiotics is mediated through a rapid increase in the conversion of UDP-glucuronate to glucuronate, which does not apparently involve a glucuronidation-deglucuronidation cycle. Expand
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TLDR
Evidence is reviewed indicating that these transport pathways are regulated under physiological conditions and altered by aging and disease. Expand
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TLDR
ERU is an extremely reactive ketose, which rapidly glycates and crosslinks proteins, and therefore may mediate the AsA-dependent modification of protein (ascorbylation) seen in vitro, and also proposed to occur in vivo in human lens during diabetic and age-onset cataract formation. Expand
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TLDR
The experiments indicate that the observed activity of mitochondria is probably due to their contamination by microsomes, and the microsomal enzyme concerned in the oxidation of L-gulonolactone to L-ascorbic acid is inhibited by heavy-metal ions and reversibly by p-chloromercuribenzoate, indicating the involvement of some essential thiol groups in the enzyme. Expand
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TLDR
Two possible pathways for the biosynthesis of n-ascorbic acid from glucose in rats have been investigated and one, involving L-sorbose as an intermediate, was ruled out in a previous isotopic study. Expand
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Abstract Aldonolactonase of the soluble fraction of rat liver has been purified 110-fold in a yield of 34% by isoelectric precipitation and heat treatment in the presence of Mn ++ , fractionationExpand
Is ascorbic acid an antioxidant for the plasma membrane?
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  • Chemistry, Medicine
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TLDR
Ascorbic acid, or vitamin C, is a primary antioxidant in plasma and within cells, but it can also interact with the plasma membrane by donating electrons to the α‐tocopheroxyl radical and a trans‐plasma membrane oxidoreductase activity, and ascorbate is the preferred electron donor within cells. Expand
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