Vitamins and Cofactors Flashcards
a biochemically active compound formed by the combination of an enzyme with a cofactor.
holoenzyme
Enzymes that require a cofactor but do not have one bound.
apoenzyme
Oxidizes ethanol to acetylaldehyde.
Gains TWO electrons
NAD+
Nicotinamide adenine dinucleotide
Vitamin precursor of NAD+ and NADP+.
Niacin (vitamin B3)
dietary source of niacin
Meat, whole grains, fortified cereal
Pellagra: characterized by dermatitis, diarrhea, and dementia
are associated with __________ deficiency.
niacin
cofactor that Oxidizes ethanol to acetylaldehyde.
Gains TWO electrons
NAD+
redox cofactor used in fuel oxidation.
NAD+
redox cofactor used in detoxification and biosynthesis.
NADP+
enzymes dependent on NAD+ and NADP+
ADH (alcohol dehydrogenase), cytochromeP450, and HMG CoA
redox cofactor that:
- accept a single electron at two separate locations
- prosthetic
FAD
Flavin adenine dinucleotide
vitamin precursor of FAD
Riboflavin (vitamin B2)
dietary sources of riboflavin
Milk, eggs, organ meats, legumes, mushrooms
pathologies of riboflavin deficiency
Cheilosis, glossitis, keratitis, seborreic dermatitis, normocytic anemia
redox cofactor creating and breaking double bonds and disulfide bonds
enzyme: succinate dehyrogenase
FAD
redox cofactor for Hydroxylase enzymes important in collagen synthesis, neurotransmitter synthesis and oxygen sensing
- also a non-enzymatic anti-oxidant
- found in citrus fruits and vegetables
ascorbic acid (vit C)
characterized by defects in connective tissue
Sx: slow wound healing, apathy/irritability, anemia, gingival lesions, enlargement of costochondral junctions, petechiae
scurvy
vitamin precursor of TPP Thiamine pyrophosphate (TPP)
thiamine
thiamine deficiency is caused by:
malnutrition, alcoholism, monotonous diet
Beriberi (I cant, I cant): characterized by headache, malaise, peripheral neuropathy (dry), and heart failure (wet)
Wernicke encephalopathy: confusion and altered mental status, abnormal eye movements, ataxia
Karsokoff psychosis: amnesia, confabulation
All are pathologies of:
thiamine deficiency
activation transfer cofactor that forms a covalent bond with lysine residue side chains on transacylase subunits of a-keto acid dehydrogenase complexes
lipoate
activation transfer cofactor that metabolizes amino acids with tranaminases. precursor: vit B6
PLP
Pyridoxal phosphate
