title: Serine transhydroxymethylase from rabbit liver. Sequence of anonapeptide at the pyridoxal-5'-phosphate-binding site.
abstract: The amino acid sequence of the coenzyme-binding site of serine transhydroxymethylase from rabbit liver has been determined. After reduction with NaBH4 and aminoethylation, a first sample of enzyme was digested with thermolysin and a single phosphopyridoxyl peptide was isolated. A second sample of similarly treated enzyme was digested with chymotrypsin and three phosphopyridoxyl peptides clearly originating from a unique coenzyme-binding site were isolated. Sequence analysis of these peptides indicate the following structure: Val-Val-Thr-Thr-His(Pxy)-Thr-Leu. Sequence homologies of the active site of various pyridoxalphosphate enzymes are discussed in terms of a possible catalytic role and of evolution of this class of proteins.
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001665:Binding Sites; D001894:Borohydrides; D012696:Glycine Hydroxymethyltransferase / Q000378:metabolism; D008099:Liver / Q000201:enzymology*; D010446:Peptide Fragments / Q000032:analysis; D011485:Protein Binding; D011732:Pyridoxal Phosphate; D011817:Rabbits; D014166:Transferases / Q000378:metabolism
chemical_list: D000596:Amino Acids; D001894:Borohydrides; D010446:Peptide Fragments; D011732:Pyridoxal Phosphate; D014166:Transferases; D012696:Glycine Hydroxymethyltransferase