Guenthner T M, Karnezis T A
Department of Pharmacology, University of Illinois College of Medicine, Chicago 60612.
J Biochem Toxicol. 1986 Dec;1(4):67-81. doi: 10.1002/jbt.2570010407.
Immunochemical techniques were used to investigate the biochemical properties of human lung epoxide hydrolases. Two epoxide hydrolases with different immunoreactive properties were identified. These two epoxide hydrolases were found in both cytosolic and microsomal cell fractions. Immunotitration of enzyme activity showed that enzymes that catalyze the hydration of benzo(a)pyrene 4,5-oxide react with antiserum to rat microsomal epoxide hydrolase; those that hydrate trans-stilbene oxide do not. Immunotitration and Western blot experiments showed that microsomal and cytosolic benzo(a)pyrene 4,5-oxide hydrolases have significant structural homology. Immunohistochemical staining of human lung benzo(a)pyrene 4,5-oxide hydrolase showed that the enzyme is localized primarily in the bronchial epithelium. No cell type-specific localization was observed. An enzyme-linked immunosorbent assay was developed which allows direct quantitation of benzo(a)pyrene 4,5-oxide hydrolase protein. Levels of enzyme protein detected by this assay correlated well with enzyme levels determined by substrate conversion assays.
采用免疫化学技术研究人肺环氧水解酶的生化特性。鉴定出两种具有不同免疫反应特性的环氧水解酶。这两种环氧水解酶存在于胞质和微粒体细胞组分中。酶活性的免疫滴定表明，催化苯并(a)芘4,5 - 氧化物水化的酶与抗大鼠微粒体环氧水解酶抗血清发生反应；而催化反式芪氧化物水化的酶则不发生反应。免疫滴定和蛋白质印迹实验表明，微粒体和胞质苯并(a)芘4,5 - 氧化物水解酶具有显著的结构同源性。人肺苯并(a)芘4,5 - 氧化物水解酶的免疫组织化学染色显示，该酶主要定位于支气管上皮。未观察到细胞类型特异性定位。开发了一种酶联免疫吸附测定法，可直接定量苯并(a)芘4,5 - 氧化物水解酶蛋白。该测定法检测到的酶蛋白水平与通过底物转化测定法确定的酶水平相关性良好。
