A comparison of pyridoxal 5'-phosphate dependent decarboxylase and transaminase enzymes at a molecular level.
Pyridoxal 5'-phosphate is a coenzyme for a number of enzymes which catalyse reactions at C alpha of amino acid substrates including transaminases, decarboxylases and serine hydroxymethyltransferase. Using the X-ray coordinates for a transaminase, aspartate aminotransferase, and the results of stereochemical and mechanistic studies for decarboxylases and serine hydroxymethyltransferase, an active-site structure for the decarboxylase group is constructed. The structure of the active-site is further refined through active-site pyridoxyllysine peptide sequence comparison and a 3-D catalytic mechanism for the L-alpha-amino acid decarboxylases is proposed. The chemistry of serine hydroxymethyltransferase is re-examined in the light of the proposed decarboxylase mechanism.
Smith
D M
DM
Department of Chemistry, University, St. Andrews, Fife, Scotland.
Thomas
N R
NR
Gani
D
D
D000595:Amino Acid Sequence; D000818:Animals; D001219:Aspartate Aminotransferases / Q000737:chemistry*; D001665:Binding Sites; D002262:Carboxy-Lyases / Q000737:chemistry*; D002384:Catalysis; D012696:Glycine Hydroxymethyltransferase / Q000737:chemistry; D006801:Humans; D008969:Molecular Sequence Data; D015394:Molecular Structure; D011487:Protein Conformation; D011732:Pyridoxal Phosphate / Q000737:chemistry*; D016415:Sequence Alignment; D013329:Structure-Activity Relationship
D011732:Pyridoxal Phosphate; D012696:Glycine Hydroxymethyltransferase; D001219:Aspartate Aminotransferases; D002262:Carboxy-Lyases