title: Clarification of mechanism of human sputum elastase inhibition by a new inhibitor, ONO-5046, using electrospray ionization mass spectrometry.
abstract: Liquid chromatography electrospray ionization mass spectrometry (LC/ESI-MS) to probe the nature of the covalent E-I complex was successfully applied to clarify the mechanism of human sputum elastase (HSE) inhibition by a new inhibitor, ONO-5046. The mass spectrum of the four HSE isozymes displayed their molecular ion peaks at m/z=26,018, 25,929, 25,200, and 25,054, respectively. Immediately after incubation, inactivation of HSE with ONO-5046 increased the four molecular ion peaks by approximately 84 amu, which was assigned to the mass unit of the pivaloyl moiety of ONO-5046. An additional minute of incubation of E-I complex restored the original molecular ion peaks. These observations strongly suggested that ONO-5046 inactivates HSE by a reversible 'acylation-deacylation' mechanism.
authors.affiliation: Medicinal Chemistry Research Laboratories, Minase Research Institute, Ono Pharmaceutical Co., Ltd., Shimamoto, Mishima, Osaka, Japan.
authors.forename: Yoshisuke
authors.initials: Y
authors.lastname: Nakayama
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Odagaki
authors.forename: Setsuko
authors.initials: S
authors.lastname: Fujita
authors.forename: Shozo
authors.initials: S
authors.lastname: Matsuoka
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Hamanaka
authors.forename: Hisao
authors.initials: H
authors.lastname: Nakai
authors.forename: Masaaki
authors.initials: M
authors.lastname: Toda
mesh_terms: D000215:Acylation; D002851:Chromatography, High Pressure Liquid; D005998:Glycine / Q000031:analogs & derivatives* / Q000494:pharmacology; D006801:Humans; D007527:Isoenzymes / Q000037:antagonists & inhibitors; D010196:Pancreatic Elastase / Q000037:antagonists & inhibitors*; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013183:Sputum / Q000201:enzymology*; D013449:Sulfonamides / Q000494:pharmacology
chemical_list: D007527:Isoenzymes; D015842:Serine Proteinase Inhibitors; D013449:Sulfonamides; C069195:sivelestat; D010196:Pancreatic Elastase; D005998:Glycine