Phosphoserine Aminotransferase 1 (PSAT1)

PSAT catalyzes the second step in the pathway, conversion of 3-phosphohydroxypyruvate into 3-phosphoserine. The full-length PSAT-beta transcript encodes a deduced 370-amino acid protein with a calculated molecular mass of 40 kD. PSAT-alpha lacks exon 8 and encodes a deduced 324-amino acid protein with a calculated molecular mass of 35.2 kD. Compared with PSAT-beta, PSAT-alpha lacks 46 amino acids. Both proteins contain a conserved binding domain for the cofactor pyridoxal 5-prime-phosphate (vitamin B6). PSAT-beta shares 92.4% amino acid similarity with its mouse homolog. PSAT-beta orthologs were present in all species examined, including plants, insects, and bacteria.