Expression in Xenopus oocytes of rat liver mRNA coding for a bile salt-dependent cholesteryl ester hydrolase.
Expression in Xenopus oocytes of rat liver mRNA coding for a bile salt-dependent cholesteryl ester hydrolase.
复制标题
编码胆汁盐依赖性胆固醇酯水解酶的大鼠肝脏 mRNA 在非洲爪蟾卵母细胞中的表达。
DOI：
10.1073/pnas.86.18.6913
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发表时间：
1989
影响因子：
11.1
通讯作者：
Fisher,EA
中科院分区：
文献类型：
--
作者：
Zolfaghari,R;Harrison,EH;Ross,AC;Fisher,EA
在非洲爪哇卵母细胞中注射大鼠肝脏mRNA，表达一种具有催化活性的胆盐依赖胆固醇酯水解酶(CEH)。表达的CEH活性高度依赖于三羟基胆盐(胆酸盐或其偶联物)的存在；在10 mM胆酸钠存在时，观察到最大的水解活性。表达的CEH不被二羟基胆盐(脱氧胆酸盐及其结合物)激活。在10 mM胆酸钠存在下，CEH活性在pH 7附近达到最大值，但在pH 6~8之间活性最高。针对大鼠胰腺CEH的单特异性免疫抗体可完全抑制非洲爪哇卵母细胞表达CEH。丝氨酸酶抑制剂苯甲基磺酰氟对CEH的表达有抑制作用，而硫醇阻断剂对氯汞苯甲酸(5 MM)对CEH的表达没有明显的抑制作用。这些实验清楚地表明，肝脏含有编码胆盐依赖的CEH活性的mRNA，并表明摄取胰酶不一定像推测的那样是肝脏CEH的来源。
A catalytically active bile salt-dependent cholesteryl ester hydrolase (CEH) was expressed when Xenopus oocytes were injected with rat liver mRNA. The expressed CEH activity was highly dependent on the presence of trihydroxy bile salts (cholate or one of its conjugates); maximum hydrolytic activity was observed in the presence of 10 mM sodium cholate. The expressed CEH was not activated by dihydroxy bile salts (deoxycholate and its conjugates). In the presence of 10 mM sodium cholate, the CEH activity was maximal near pH 7 but was significant between pH 6 and 8. Monospecific immune IgG raised against rat pancreatic CEH completely inhibited the CEH expressed in Xenopus oocytes. Phenylmethylsulfonyl fluoride, a serine enzyme inhibitor, was inhibitory to the expressed CEH activity, whereas p-chloromercuribenzoate (up to 5 mM), a potent thiol-blocking agent, did not significantly inhibit the expressed activity. These experiments clearly demonstrate that the liver contains an mRNA encoding a bile salt-dependent CEH activity and suggest that the uptake of pancreatic enzyme is not necessarily the source of liver CEH as has been speculated.