HIGH YIELD POINT FOR BIOCHEMISTRY 2015
IMPORTANT POINT ABOUT Amino Acid .
Glycine: • smallest amino acid. inhibitory neurotransmitter in spinal cord (blocked by toxm in tetanus), synthesis of heme and collagen and bile salts and acids
Alanine: • alanine cycle during fasting. major substrate for gluconeogenesis (transarninated mto pyruvate)
Valine: • essential A..A.. • branched-chain amino acid.> not degraded in liver. • utilized by muscle.
• increased in maple syrup urine disease
Leucine: • essential A.A… • branched-chain amino acid. • not degraded in liver. • kerogenic, •
utilized by muscle, • increased in maple syrup urine disease
Isoleucine: • essential .A…/\.• • branched-chain amino acid, • not degraded in liver. • utilized by
muscle, • increased in maple S)’TUp urine disease
Methionine: • essential A.A. • polypeptide chain initiation, • methyl donor (as S·adenosyl methionine)
Proline: • helix breaker. • only amino acid with side chain attached to a-amino group. • hydroxylation in collagen aided by ascorbic acid, • binding site for cross-bridges in collagen Phenylalanine: • essential A.A. • increased in phenylketonuria (PKC). • aromatic side chains: increased in hepatic coma
Trypropban: •essential AA, • serotonin. niacin, and melatonin precursor. • aromatic side chains:
increased in hepatic coma
Cvsteiue: • forms disulfide bonds,• component of glutathione, an important antioxidant in RBCs
(deficient in G6PD deficiency}
Serine: • single-carbon donor: converted into glycine when carbon removed. • phosphorylatcd by
k.nases
Threonine: • essential A..A. • phosphorylated by kinases
Tyrosine: • precursor of catecholamines, melanin, thyroid hormones. • phosphory lated by
kinases: important in second messengers. • aromatic side chains: increase in hepatic coma. • must be supplied in diet in phenylketonuria