title: Identification of the catalytic histidine residue participating in the charge-relay system of carboxypeptidase Y.
abstract: The essential histidine residue of carboxypeptidase Y (CPY) was modified by a site-specific reagent, a chloromethylketone derivative of benzyloxycarbonyl-L-phenylalanine. The single modified histidine residue was converted to N tau-carboxy-methyl histidine (cmHis) upon performic acid oxidation. A peptide containing cmHis was isolated from the tryptic-thermolytic digest. Based on the amino acid composition and sequence analysis, the peptide is shown to be Val-Phe-Asp-Gly-Gly-cmHis-MetO2-Val-Pro, which was derived from CPY cleaved by trypsin at Arg 391 and thermolysin at Phe 401, and thus His 397 was modified. This histidine residue has been implicated previously by X-ray analysis to participate in the charge-relay system of CPY.
authors.affiliation: Department of Agricultural Chemistry, Faculty of Agriculture, Kyoto University, Japan.
authors.forename: G
authors.initials: G
authors.lastname: Jung
authors.forename: H
authors.initials: H
authors.lastname: Ueno
authors.forename: R
authors.initials: R
authors.lastname: Hayashi
authors.forename: T H
authors.initials: TH
authors.lastname: Liao
mesh_terms: D000590:Amino Acid Chloromethyl Ketones / Q000737:chemistry; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D001665:Binding Sites; D002268:Carboxypeptidases / Q000737:chemistry* / Q000378:metabolism; D043402:Cathepsin A; D002851:Chromatography, High Pressure Liquid; D005561:Formates; D006639:Histidine / Q000737:chemistry* / Q000378:metabolism; D007202:Indicators and Reagents; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010446:Peptide Fragments / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D013329:Structure-Activity Relationship; D013820:Thermolysin / Q000378:metabolism; D014357:Trypsin / Q000378:metabolism
chemical_list: D000590:Amino Acid Chloromethyl Ketones; D000596:Amino Acids; D005561:Formates; D007202:Indicators and Reagents; D010446:Peptide Fragments; C008817:peroxyformic acid; C006735:ZPCK; D006639:Histidine; D002268:Carboxypeptidases; D043402:Cathepsin A; D014357:Trypsin; D013820:Thermolysin