The human body can synthesize non-essential amino acids through various metabolic pathways. Non-essential amino acids are those that can be produced by the body and are not required to be obtained through the diet. There are 11 non-essential amino acids: alanine, arginine, asparagine, aspartate, cysteine, glutamate, glutamine, glycine, proline, serine, and tyrosine.Here are some key enzymes and pathways involved in the biosynthesis of non-essential amino acids:1. Alanine: Alanine is synthesized from pyruvate through the action of the enzyme alanine aminotransferase ALT . This enzyme catalyzes the transfer of an amino group from glutamate to pyruvate, forming alanine and -ketoglutarate.2. Arginine: Arginine is synthesized through the urea cycle, which is a series of biochemical reactions that occur in the liver. Key enzymes involved in arginine synthesis include carbamoyl phosphate synthetase I, ornithine transcarbamylase, and argininosuccinate synthetase.3. Asparagine: Asparagine is synthesized from aspartate by the enzyme asparagine synthetase. This enzyme catalyzes the transfer of an amino group from glutamine to aspartate, forming asparagine and glutamate.4. Aspartate: Aspartate is synthesized from oxaloacetate through the action of the enzyme aspartate aminotransferase AST . This enzyme catalyzes the transfer of an amino group from glutamate to oxaloacetate, forming aspartate and -ketoglutarate.5. Cysteine: Cysteine is synthesized from serine and homocysteine through the action of the enzyme cystathionine -synthase. This enzyme catalyzes the formation of cystathionine from serine and homocysteine, which is then converted to cysteine by the enzyme cystathionine -lyase.6. Glutamate: Glutamate is synthesized from -ketoglutarate through the action of the enzyme glutamate dehydrogenase. This enzyme catalyzes the reductive amination of -ketoglutarate, forming glutamate.7. Glutamine: Glutamine is synthesized from glutamate by the enzyme glutamine synthetase. This enzyme catalyzes the addition of an amino group from ammonia to glutamate, forming glutamine.8. Glycine: Glycine is synthesized from serine through the action of the enzyme serine hydroxymethyltransferase. This enzyme catalyzes the transfer of a one-carbon unit from serine to tetrahydrofolate, forming glycine and 5,10-methylene tetrahydrofolate.9. Proline: Proline is synthesized from glutamate through a series of reactions involving the enzymes glutamate 5-kinase, glutamate 5-semialdehyde dehydrogenase, and pyrroline-5-carboxylate reductase.10. Serine: Serine is synthesized from 3-phosphoglycerate, an intermediate of glycolysis, through the action of the enzymes phosphoglycerate dehydrogenase, phosphoserine aminotransferase, and phosphoserine phosphatase.11. Tyrosine: Tyrosine is synthesized from phenylalanine through the action of the enzyme phenylalanine hydroxylase. This enzyme catalyzes the hydroxylation of phenylalanine to form tyrosine.These biosynthetic pathways allow the body to produce non-essential amino acids as needed, ensuring that the necessary building blocks for protein synthesis are available.