title: Bleomycin hydrolase is a unique thiol aminopeptidase.
abstract: Bleomycin hydrolase, which hydrolyzes the carboxamide bond in the pyrimidoblamic acid moiety of the bleomycin molecule, also cleaved several p-nitroanilide substrates with a neutral or basic amino acid residue and dipeptide substrates such as L-leucyl-glycine. The activity of bleomycin hydrolase was inhibited by two thiol protease inhibitors, E-64 and leupeptin, as well as by N-ethylmaleimide. These results suggest that bleomycin hydrolase is a thiol aminopeptidase. Magnesium ion, sodium chloride, ethylenediaminetetraacetic acid and 1,2-dihydroxybenzene-3,5-disulfonic acid specifically activated the enzymatic hydrolysis of L-arginine-p-nitroanilide, but did not that of L-leucine-p-nitroanilide. Lineweaver-Burk plots showed that Km values of the enzymatic activity for L-arginine-p-nitroanilide were altered by these reagents, although Vmax values were almost unaltered.
authors.affiliation: Institute of Applied Microbiology, University of Tokyo, Japan.
authors.forename: C
authors.initials: C
authors.lastname: Nishimura
authors.forename: H
authors.initials: H
authors.lastname: Suzuki
authors.forename: N
authors.initials: N
authors.lastname: Tanaka
authors.forename: H
authors.initials: H
authors.lastname: Yamaguchi
mesh_terms: D014013:1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt; D002614:Chelating Agents; D003546:Cysteine Endopeptidases; D004492:Edetic Acid; D006026:Glycoside Hydrolases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006868:Hydrolysis; D007700:Kinetics; D008274:Magnesium / Q000378:metabolism; D012965:Sodium Chloride / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D002614:Chelating Agents; D012965:Sodium Chloride; D014013:1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt; D004492:Edetic Acid; D006026:Glycoside Hydrolases; D003546:Cysteine Endopeptidases; C031262:bleomycin hydrolase; D008274:Magnesium