Preferred Label : Vitamin C in Brain Pathway;
NCIt related terms : Vitamin C in the Brain;
Alternative definition : BIOCARTA: Vitamin C (ascorbic acid) was first identified by virtue of the essential
role it plays in collagen modification, preventing the nutritional deficiency scurvy.
Vitamin C acts as a cofactor for hydroxylase enzymes that post-translationally modify
collagen to increase the strength and elasticity of tissues. Vitamin C reduces the
metal ion prosthetic groups of many enzymes, maintaining activity of enzymes, and
also acts as an anti-oxidant. Although the prevention of scurvy through modification
of collagen may be the most obvious role for vitamin C, it is not necessarily the
only role of vitamin C. Svct1 and Svct2 are ascorbate transporters for vitamin C import
into tissues and into cells. Both of these transporters specifically transport reduced
L-ascorbic acid against a concentration gradient using the intracellular sodium gradient
to drive ascorbate transport. Svct1 is expressed in epithelial cells in the intestine,
upregulated in cellular models for intestinal epithelium and appears to be responsible
for the import of dietary vitamin C from the intestinal lumen. The vitamin C imported
from the intestine is present in plasma at approximately 50 uM, almost exclusively
in the reduced form, and is transported to tissues to play a variety of roles. Svct2
imports reduced ascorbate from the plasma into very active tissues like the brain.
Deletion in mice of the gene for Svct2 revealed that ascorbate is required for normal
development of the lungs and brain during pregnancy. A high concentration of vitamin
C in neurons of the developing brain may help protect the developing brain from free
radical damage. The oxidized form of ascorbate, dehydroascorbic acid, is transported
into a variety of cells by the glucose transporter Glut-1. Glut-1, Glut-3, and Glut-4
can transport dehydroascorbate, but may not transport significant quantities of ascorbic
acid in vivo. (This definition may be outdated - see the DesignNote.);
NCIt note : The BIOCARTA Definition (ALT_DEFINITION) for this pathway concept was provided by
BioCarta. This property was not created by, nor is it maintained by the NCI Thesaurus
staff. Additionally, BioCarta is no longer updating its pathway data; thus, the BIOCARTA
Definition might be outdated or inaccurate. Please see the Terms and Conditions for
Use at http://www.biocarta.com/.;
Biocarta ID : h_vitCBPathway;
Origin ID : C39267;
UMLS CUI : C1520058;
Semantic type(s)
- has_gene_product_element
- pathway_has_gene_element
