title: Amino acid sequence around a cysteine residue in the active center of jack bean urease.
abstract: Cysteine residues in the active center of jack bean urease [EC 3.5.1.5] were modified with 14C-labeled diazonium-1H-tetrazole (DHT). The labeled enzyme was carboxymethylated with iodoacetic acid, and then hydrolyzed with trypsin. The tryptic digest was subjected to gel filtration on Sephadex G-50, yielding two radioactive fractions. The [14C]DHT-labeled peptide having a lower molecular weight, which was determined to be approximately 1,000 by the method of gel filtration, was further purified to homogeneity by ion-exchange chromatography on DEAE-Sephadex A-25. [14C]DHT-labeled cysteine was identified as cysteic acid after performic acid oxidation, and the amino acid sequence of the low-molecular-weight [14C]DHT-labeled peptide was determined to be Phe-Glu-Pro-Gly-Asp-Cys-Asn-Ser-Thr-Phe-Lys.
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D055598:Chemical Phenomena; D002621:Chemistry; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D003545:Cysteine; D007887:Fabaceae / Q000201:enzymology*; D010446:Peptide Fragments; D010946:Plants, Medicinal; D013777:Tetrazoles; D014357:Trypsin; D014510:Urease / Q000302:isolation & purification*
chemical_list: D010446:Peptide Fragments; D013777:Tetrazoles; C007314:5-diazo-1H-tetrazole; D014357:Trypsin; D014510:Urease; D003545:Cysteine