6 - Individual Vitamins Flashcards
Vitamin A
Provitamin A “Carotenoids” (ex: Beta Carotene) Mature Retinoids (ex: retinal, retinol, retinoic acid) Deficiency results in: night blindness, xeropthalmia (dry eyes)
Vitamin D “calitriol”
Conditional vitamin - taken from diet “ergocalciferol” or sunlight “7-dehydrocholesterol” Provitamin D “cholecalciferol” Converted to calcidiol and calcitriol Deficiency results in: osteomalacia
Vitamin E
Most prominent form is d-alpha-tocopherol. Is a fat soluble antioxidant.
Vitamin K
Co-enzyme in carboxylation, specifically glutamyl residues during synthesis of prothrombin and clotting factors. Product is gamma carboxyl-glutamate (Gla).
Forms of Vitamin K: Phylloquinone Menaquinone Menadione
Phylloquinone - found in vegetables Menaquinone - found in intestinal bacteria Menadione - synthetic Vitamin K
Folic Acid “Tetrahydrofolate”
Consists of pteroic acid, PABA, and glutamate
Function:
- synthesis of purine nucleotides
- thymidylate synthase reaction
Vitamin C “ascorbic acid”
Synthesis of bile, carnitine, dopamine
Hydroxylation of lysyl and prolyl residues in procollagen
Reduction of ferric to ferrous iron for absorption in gut
Deficiency results in: scurvy (argh!)
Vitamin B6 “pyridoxal phosphate”
Dietary precursors: pyridoxine, pyridoxal, pyridoxamine
Vitamer - can have many forms
Functions: Synthesis of neurotransmitters (serotonin, norepinephrine, GABA). Production of niacin from tryptophan
Thyamine “thiamine pyrophosphate”
Functions: conversion of pyruvate to acetyl CoA by PDHC
Deficiency is Beriberi and Wernicke-Korsakoff Syndrome
Niacin “nicotinic acid and nicotinamide”
Functions: as NAD in redox reactions, NADP in reductive biosynthesis
Deficiency: pellagra (dermatitis, diahrrea, dementia, death)
Can be synthesized from tyrptophan
Vitamin B2 “riboflavin”
Pathway:
Riboflavin => FMN => FAD
Function: redox reactions like ETC, TCA cycle
Is light sensitive
