title: Lysine as the substrate binding site of porphobilinogen synthase of Rhodopseudomonas spheroides.
abstract: The 14C labelled inactive protein obtained by sodium borohydride reduction of the enzyme, porphobilinogen synthase of Rhodopseudomonas spheroides, in the presence of [4-14C]5-aminolevulinic acid, gave on acid hydrolysis and subsequent electrophoresis or two-dimensional chromatography a major radioactive spot which was confirmed to be N-epsilon-[4-(-5aminovaleric acid)]lysine (ALA-lysine) by comparing its co-chromatographic and electrophoretic behaviour with the chemically synthesized ALA-lysine. An epsilon-NH2 group of lysine residue of porphobilinogen synthase, is thus the binding site of the substrate, 5-aminolevulinic acid.
mesh_terms: D000622:Aminolevulinic Acid; D001665:Binding Sites; D008239:Lysine; D000623:Porphobilinogen Synthase / Q000378:metabolism*; D011485:Protein Binding; D012242:Rhodobacter sphaeroides / Q000201:enzymology*
chemical_list: D000622:Aminolevulinic Acid; D000623:Porphobilinogen Synthase; D008239:Lysine