BiosynthesisofGlycineandSerine

Intermediates in energy production pathways such as glycolysis and the Kreb's cycle are commonly the starting point for the biosynthesis of amino acids. The glycolytic intermediate 3-phosphoglycerate is the starting point for the biosynthesis of serine and glycine. First, 3-phosphoglycerate is oxidized and then transaminated to produce 3-phosphoserine. Phosphoserine hydrolase hydrolyzes the phosphate in 3-phosphoserine to produce serine. The side chain carbon of serine is removed to create glycine, which has only hydrogen as its side chain. The removal of the serine side chain is accomplished by transferring the carbon to tetrahydrofolate, a carrier of one-carbon groups. Genetic deficiency of the first enzyme in the pathway, 3-phosphoglycerate dehydrogenase, leads to impaired myelination of neurons and impaired development of the central nervous system.