title: Identification of lysine at the active site of human 5-aminolaevulinate dehydratase.
abstract: Reduction of human 5-aminolaevulinate dehydratase with NaBH4 in the presence of 14C-labelled substrate led to complete loss of catalytic activity and to incorporation of label into the enzyme protein. By comparison with authentic lysyl-aminolaevulinic acid, prepared chemically, the modified active-site amino acid obtained by acid hydrolysis was shown to be lysine. Sequencing of a CNBr-cleavage peptide isolated from the inactivated 14C-labelled enzyme revealed that the lysine was present within the sequence M-V-K-P-G-M.
mesh_terms: D000595:Amino Acid Sequence; D000622:Aminolevulinic Acid / Q000378:metabolism; D001665:Binding Sites; D001894:Borohydrides; D006801:Humans; D008239:Lysine / Q000032:analysis*; D010084:Oxidation-Reduction; D010446:Peptide Fragments / Q000032:analysis; D000623:Porphobilinogen Synthase / Q000378:metabolism*
chemical_list: D001894:Borohydrides; D010446:Peptide Fragments; C025364:sodium borohydride; D000622:Aminolevulinic Acid; D000623:Porphobilinogen Synthase; D008239:Lysine