Characterization of multiple forms of cholesteryl ester hydrolase in the rat testis.

摘要: Cholesterol ester hydrolase (EC 3.1.1.13) activity from the 104,000 X g supernatant of rat testis was fractionated into 28-kDa, 72-kDa, and 420-kDa molecular mass forms by high performance size exclusion chromatography. The 72-kDa (temperature-labile) were completely inactivated elevation temperature 32 to 37 degrees C. Apparent disaggregation form suggested that enzymes are monomeric multimeric same enzyme. 28-kDa shown be a different enzyme (temperature-stable) which retained at In contrast, cholesteryl activities supernatants liver or adrenal gland unaffected increased 4-fold, respectively, Both testicular exhibited pH optima about 7.3, activated sodium cholate concentrations near critical micellar concentration (0.03-0.07%), but inhibited higher concentrations. temperature-labile specificity for esters monoenoic fatty acids 18-24 carbons, especially nervonate (24:1), whereas temperature-stable highest oleate arachidonate. Neither hydrolyzed acetate, myristate, palmitate, linoleate, docosahexaenoate . reached maximum rates hydrolysis 150 microM substrates, with each substrate both reaction temperatures. Substrate inhibition observed (200 microM). induced 20-fold in hypophysectomized rats injection follicle-stimulating hormone (FSH) localized Sertoli cells, target cells FSH, not luteinizing hormone. FSH LH found Leydig respective present detectable levels germinal cells. unique properties, localization, hormonal regulation cholesterol hydrolases suggest important roles these testis.