title: The effect of L-ascorbate on catecholamine biosynthesis.
abstract: l-Ascorbate stimulates the enzymic hydroxylation of phenylalanine in vitro by recycling tetrahydrobiopterin, which reduces O(2) utilized in the reaction. It is suggested that ascorbate might have a similar function in vivo; this would explain the apparent regulation of tyrosine hydroxylase and tryptophan hydroxylase activities by this vitamin.
mesh_terms: D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology* / Q000502:physiology; D002247:Carbon Isotopes; D002395:Catecholamines / Q000096:biosynthesis*; D005260:Female; D008099:Liver / Q000201:enzymology; D009249:NADP; D010084:Oxidation-Reduction; D010651:Phenylalanine Hydroxylase / Q000378:metabolism*; D011621:Pteridines; D051381:Rats; D013997:Time Factors; D014365:Tryptophan Hydroxylase / Q000378:metabolism; D014443:Tyrosine; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
chemical_list: D002247:Carbon Isotopes; D002395:Catecholamines; D011621:Pteridines; D014443:Tyrosine; D009249:NADP; D010651:Phenylalanine Hydroxylase; D014446:Tyrosine 3-Monooxygenase; D014365:Tryptophan Hydroxylase; D001205:Ascorbic Acid