The pyridoxal-binding site in pyridoxamine-pyruvate transaminase.
The enzyme-substrate complex formed between pyridoxamine-pyruvate transaminase (EC 2.6.1.30) and pyridoxal was reduced with NaBH4. After carboxymethylation and tryptic digestion, pyridoxyl-lysine-containing peptides were isolated by a combination of Sephadex and Dowex 50 chromatography. Analysis of these peptides shows the structure around the pyridoxal-binding lysine residues to be Ala-Asp-Ile-Tyr-Val-Thr-Gly-Pro-Asx-Lys(Pxy)-Cys-Leu(Pro2, Gly2, Ala2, Met)(Thr, Leu2)Gly-Val-Ser-Glu-Arg. This structure differs from those found for the corresponding peptides from pyridoxal phosphate-dependent enzymes.
D000596:Amino Acids / Q000032:analysis; D001665:Binding Sites; D010446:Peptide Fragments / Q000032:analysis; D011730:Pyridoxal / Q000378:metabolism*; D011733:Pyridoxamine; D000637:Transaminases / Q000378:metabolism*
D000596:Amino Acids; D010446:Peptide Fragments; D011730:Pyridoxal; D011733:Pyridoxamine; D000637:Transaminases