Vitamin C

  title={Vitamin C},
  author={Carole L. Linster and Emile Van Schaftingen},
  journal={The FEBS Journal},
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… 
An Overview of the Characteristics and Function of Vitamin C in Various Tissues: Relying on its Antioxidant Function
The wide role of ascorbate, a neuromodulator of glutamatergic and dopaminergic system and related behaviors, also improves components of the immune system.
Vitamin C transporters
In humans, the maintenance of a low daily requirement of vitamin C is attained through an efficient system for the recycling of the vitamin involving the two families of vitaminC transporters.
Ascorbate is a multifunctional micronutrient whose synthesis is lacking in primates
  • J. Fujii
  • Biology
    Journal of clinical biochemistry and nutrition
  • 2021
It is proposed that an enhanced glucuronate conjugation reaction may have applied positive selection pressure on ascorbate-incompetent animals, thus allowing them to dominate the animal kingdom.
The Myo‐inositol pathway does not contribute to ascorbic acid synthesis
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.
The terminal step in vitamin C biosynthesis in Trypanosoma cruzi is mediated by a FMN-dependent galactonolactone oxidase.
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.
Ascorbic acid metabolism and functions: A comparison of plants and mammals
  • N. Smirnoff
  • Biology, Environmental Science
    Free radical biology & medicine
  • 2018
Industrial production of L-ascorbic Acid (vitamin C) and D-isoascorbic acid.
Novel enzymes were identified that generate L-ascorbic acid directly via oxidation of L-sorbosone, an intermediate of the bio-oxidation of D-sorbitol to 2KGA, obviating the need for chemical rearrangement of2KGA.
The evolution of vitamin C biosynthesis and transport in animals
The simultaneous study, for the first time, of GULO, Regucalcin and SVCT s evolution provides a clear picture of VC synthesis/acquisition and reveals very different selective pressures in different animal taxonomic groups.
Vitamin C: update on physiology and pharmacology
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.
Vitamin C in Plants: From Functions to Biofortification
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.


Glucuronate, the precursor of vitamin C, is directly formed from UDP‐glucuronate in liver
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.
L-ascorbic acid biosynthesis.
Vitamin C transport systems of mammalian cells
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.
Rapid Stimulation of Free Glucuronate Formation by Non-glucuronidable Xenobiotics in Isolated Rat Hepatocytes*
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.
Regulation of vitamin C transport.
Evidence is reviewed indicating that these transport pathways are regulated under physiological conditions and altered by aging and disease.
Biological synthesis of L-ascorbic acid in animal tissues: conversion of L-gulonolactone into L-ascorbic acid.
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.
Is ascorbic acid an antioxidant for the plasma membrane?
  • J. M. May
  • Biology
    FASEB journal : official publication of the Federation of American Societies for Experimental Biology
  • 1999
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.