title: Hydrolysis of neo-kyotorphin (Thr-Ser-Lys-Tyr-Arg) and [Met]enkephalin-Arg6-Phe7 by angiotensin-converting enzyme from monkey brain.
abstract: Angiotensin-converting enzyme (ACE; dipeptidyl carboxypeptidase, EC 3.4.15.1) from monkey brain was partially purified 274-fold with 4.5% yield. The optimum pH of the enzyme was 8.2, and its Km was 3.3 mM, with hippuryl-His-Leu as the substrate in 300 mM NaCl. Its molecular weight (Mr) was estimated to be approximately 260,000 by gel filtration on Sephadex G-200. On high-performance liquid chromatographic analysis, ACE hydrolyzed neo-kyotorphin Thr-Ser-Lys-Tyr-Arg) with liberation of kyotorphin (Tyr-Arg), the [Met]enkephalin releaser. ACE also converted [Met]enkephalin-Arg6-Phe7 to [Met]enkephalin; then the enzyme slowly hydrolyzed the resulting [Met]enkephalin. The Km values of the enzyme for neo-kyotorphin and [Met]enkephalin-Arg6-Phe7 were 0.58 and 0.30 mM respectively. Thus, brain ACE may have a role in the formation of kyotorphin and [Met]enkephalin from their precursors but has little part in [Met]enkephalin degrading processes.
mesh_terms: D000806:Angiotensin-Converting Enzyme Inhibitors; D000818:Animals; D001921:Brain / Q000201:enzymology*; D002851:Chromatography, High Pressure Liquid; D004723:Endorphins / Q000378:metabolism*; D004744:Enkephalin, Methionine / Q000031:analogs & derivatives* / Q000378:metabolism; D006868:Hydrolysis; D007700:Kinetics; D008252:Macaca fascicularis; D007703:Peptidyl-Dipeptidase A / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D004723:Endorphins; D004744:Enkephalin, Methionine; C027511:enkephalin-Met, Arg(6)-Phe(7)-; C036450:neo-kyotorphin; D007703:Peptidyl-Dipeptidase A