General Veterinary Biochemistry

IMPORTANCE OF AMINO ACIDS

• It is the component of proteins.
• Glycine and g - aminobutyric acid (a glutamate decarboxylation product) and dopamine (a tyrosine product) are neurotransmeters.
• Histamine (the decarboxylation product of histidine), a vasodialator.
• Tyrosine is the precursor of the hormones thyroxine, epinephrine. The pigment melanin is also derived form tyrosine.
• Citrulline and ornithine are important intermediates in urea cycle.
• Homocysteine, an intermediate in the synthesis of methionine, s-adenosylmethionine a biological methylating agent
• Purines and pyrimidines are derived in part from amino acids.
• Sphingosine an intermediate in the synthesis of sphingolipids comes from serine.
• The neurotransmitter, 5- hydroxytryptamine (serotonin) and the nicotinamide ring of NAD are synthesized from tryptophan.
• Glutathione: (g -Glu-Cys-Gly) a tripeptide containing sulfhydril group protects red cell from oxidative damage. Glutathione also plays a key role in detoxification by reacting with the hydrogen peroxide and organic peroxides, the harmful byproduct formed during the metabolic reactions.
• NO, a vasodilator is produced from the amino acid arginine.
• Heme of hemoglobin is synthesized from the amino acid glycine and succinyl CoA.
• Creatine phosphate (a high energy molecule) present in muscle is synthesized from glycine, arginine and methionine.