Biotin Flashcards
Biotin is sometimes called:
anti-egg white injury factor
-Biotin functions as _____ _____ in carboxylation reactions
carboxyl carrier
-4 forms of carboxyl carrier/ enzyme in carboxylation reactions
Pyruvate carboxylase,
acetyl CoA carboxylase,
propionyl CoA carboxylase and
3-methylcrotonyl-CoA carboxylase
-Meets the needs for GLUCOSE when not sufficient from the diet.
during Gluconeogenesis.
- Source of energy for RBC and nervous system
2. Only fuel for the muscles during anaerobic conditions
pyruvate carboxylase
-is a biotin-dependent enzyme that catalyzes the irreversible carboxylation of acetyl-CoA to produce malonyl-CoA through its two catalytic activities, biotin carboxylase and carboxyltransferase.
Acetyl CoA carboxylase
-Converts odd chain fatty acid
-> gluconeogenesis
-catalyses the carboxylation reaction of propionyl CoA in the mitochondrial matrix.
Propionyl CoA carboxylase
-Food Sources
- Widely distributed in food, synthesized by the microflora*
- ◦Milk, liver, egg yolk, dried soya beans, peanuts, yeast, wheat bran, oatmeal and some vegetables
- ◦Bioavailability varies because of digestibility
- ◦Unstable in oxidizing conditions and heat
- liver glandular organs
Deficiency is induced by feeding ____
raw egg white (avidin)
Deficiency symptoms
◦seborrhaic dermatitis, alopecia, and paralysis
Effects of Deficient Intakes GI tract disorder, infants receiving breastmilk with low biotin, incomplete parenteral nutrition
◦dermatitis, glossitis, anorexia, nausea, depression, fatty liver, and hypercholesterolemia
Effects of Excessive Intakes
No toxic effects even in large amounts
The chief source of biotin
Coenzyme factor in carbon dioxide fixation
biotin together with ______ it helps in the synthesis of purines, pyrimidines, fatty acids and carboxylation reactions.
active acetate (CoA)
