氟化钠和氯化钴对大鼠肠黏膜微粒体和胞质酯酶对映体选择性的影响。
Effects of sodium fluoride and cobalt chloride on the enantioselectivity of microsomal and cytosolic esterases in rat intestinal mucosa.
作者信息
Yang S K, Chang W C, Huang J D
机构信息
Department of Pharmacology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799.
出版信息
Biochem Pharmacol. 1993 Oct 19;46(8):1511-4. doi: 10.1016/0006-2952(93)90120-l.
The effects of sodium fluoride (NaF) and cobalt chloride (CoCl2) on the enantioselective hydrolysis of racemic oxazepam 3-acetate (rac-OXA) by microsomal and cytosolic esterases in rat intestinal mucosa were studied. Microsomal and cytosolic esterases hydrolyzed S-OXA and R-OXA in approximately 1:19 and 4:1 ratios, respectively. The hydrolysis of R-OXA by microsomal esterases was inhibited by NaF with an IC50 of 13.4 +/- 1.5 mM. Hydrolyses of both S-OXA and R-OXA by cytosolic esterases were inhibited by NaF with a similar IC50 value (approximately 3 mM). The hydrolysis of S-OXA by cytosolic esterases was inhibited by CoCl2 (IC50 = approximately 5 mM), whereas the hydrolysis of R-OXA by cytosolic esterases was stimulated by approximately 10% in the presence of 1 mM CoCl2. In comparison, the hydrolysis of R-OXA by microsomal esterases was stimulated by approximately 55% in the presence of 1 mM CoCl2. These results not only revealed the effects of NaF and CoCl2 on the catalytic activities of enantioselective cytosolic and microsomal esterases, but also indicated that microsomal and cytosolic esterases that selectively hydrolyzed R-OXA were distinctly different protein entities.
研究了氟化钠（NaF）和氯化钴（CoCl2）对大鼠肠黏膜微粒体和胞质酯酶催化外消旋奥沙西泮3 - 乙酸酯（rac - OXA）对映体选择性水解的影响。微粒体和胞质酯酶分别以约1:19和4:1的比例水解S - OXA和R - OXA。NaF抑制微粒体酯酶对R - OXA的水解，IC50为13.4±1.5 mM。NaF以相似的IC50值（约3 mM）抑制胞质酯酶对S - OXA和R - OXA的水解。CoCl2抑制胞质酯酶对S - OXA的水解（IC50约为5 mM），而在1 mM CoCl2存在下，胞质酯酶对R - OXA的水解被刺激约10%。相比之下，在1 mM CoCl2存在下，微粒体酯酶对R - OXA的水解被刺激约55%。这些结果不仅揭示了NaF和CoCl2对映体选择性胞质和微粒体酯酶催化活性的影响，还表明选择性水解R - OXA的微粒体和胞质酯酶是明显不同的蛋白质实体。
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