title: Identification and characterization of two distinct kyotorphin-hydrolyzing enzymes in rat brain.
abstract: We identified and characterized two kyotorphin-hydrolyzing peptidases (KTPases) in a soluble fraction of rat brain. When the soluble fraction was chromatographed with DEAE-Sephacel, the enzyme activity was resolved into two peaks, which were designated as KTPases I and II in their order of elution. KTPases I and II accounted for 95% and 5% of the KTPase activity in the soluble fraction, respectively. KTPases I and II hydrolyzed kyotorphin with Km values of 22 microM and 110 microM, respectively. By gel filtration, Mr values of KTPases I and II were determined to be 55,000 and 98,000, respectively. Immunological analyses of KTPase II with an anti-enkephalin aminopeptidase antibody indicated that KTPase II was identical to an enkephalin aminopeptidase with Mr = 98,000. However, KTPase I was a novel peptidase responsible for the major kyotorphin-degrading activity in the soluble fraction of rat brain.
authors.affiliation: Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Hiroshima, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Akasaki
authors.forename: A
authors.initials: A
authors.lastname: Nakamura
authors.forename: H
authors.initials: H
authors.lastname: Shiomi
authors.forename: H
authors.initials: H
authors.lastname: Tsuji
mesh_terms: D000626:Aminopeptidases / Q000037:antagonists & inhibitors / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000201:enzymology*; D002850:Chromatography, Gel; D003600:Cytosol / Q000201:enzymology; D004150:Dipeptidases / Q000302:isolation & purification / Q000378:metabolism; D004723:Endorphins / Q000378:metabolism*; D015151:Immunoblotting; D007163:Immunosorbent Techniques; D007930:Leucine / Q000031:analogs & derivatives / Q000494:pharmacology; D008297:Male; D008970:Molecular Weight; D010447:Peptide Hydrolases / Q000302:isolation & purification / Q000378:metabolism*; D011480:Protease Inhibitors / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D004723:Endorphins; D011480:Protease Inhibitors; C019448:kyotorphin; D010447:Peptide Hydrolases; D000626:Aminopeptidases; C025579:enkephalin degrading enzyme; D004150:Dipeptidases; C073383:kyotorphin I dipeptidase; D007930:Leucine; C012211:ubenimex