The following points highlight the top thirteen mechanisms of amino acids in body.
1. The amino acids are required for the synthesis of protein.
2. These are utilized for the synthesis of methionine which is methyl donor. This methyl donor is required for the synthesis of choline, betaine, creatine and epinephrine. Methionine can also be converted into cystine when this amino acid is inadequately supplied in the diet.
3. Phenylalanine can be converted into tyrosine and tyrosine is the precursor of epinephrine, thyroxine and the pigment melanin.
4. Glycine, arginine and methionine all participate in the synthesis of creatine.
5. Glutamine, formed from glutamate, is the chief source of ammonia formation in the kidney. Ammonia helps in the neutralization of acid to be excreted.
6. Glycine acts as a coupling agent to convert benzoic and salicylic acids into hippuric acid and salicyluric acid, respectively, which are readily excreted by the kidney.
7. Histidine can be decarboxylated to produce histamine.
8. Tryptophan can be converted into nicotinic acid in presence of vitamin B6 and B2 and into serotonin which on acetylation and methylation produces the hormone melatonin.
9. Glutamate, aspartate and the ammonia formed from amino acids by deamination are utilized for purine and pyrimidine synthesis.
10. Glutamate and aspartate are involved in transamination reaction to form keto acids which are converted into glucose by gluconeogenesis.
11. Alanine, on deamination, forms pyruvic acid which is an important intermediate compound in the metabolism of glucose. The fate of alanine is the same as that of glucose. Hence, alanine can be regarded as a glucose-former.
12. In case the diet contains more proteins than is required to replace the catabolized protein, the excess of amino acids is used for energy production. The presence of an oxidative deaminating enzyme system in the liver (and kidney) can convert amino acids into keto acids liberating ammonia in the free state. The ammonia is used for the synthesis of urea.
13. Some of the amino acids are metabolized to glucose derivatives while others form acetoacetate.