Subcellular localization of squalene synthase in rat hepatic cells. Biochemical and immunochemical evidence.
Subcellular localization of squalene synthase in rat hepatic cells. Biochemical and immunochemical evidence.
复制标题
DOI：
10.1016/s0021-9258(18)31462-5
复制
发表时间：
1993-06
期刊：
影响因子：
--
通讯作者：
K. D. Stamellos;J. E. Shackelford;I. Shechter;G. Jiang;D. Conrad;G. Keller;S. Krisans
中科院分区：
文献类型：
--
作者：
K. D. Stamellos;J. E. Shackelford;I. Shechter;G. Jiang;D. Conrad;G. Keller;S. Krisans
In the present study we investigated the subcellular localization of squalene synthase (farnesyl-diphosphate:farnesyl-diphosphate farnesyltransferase, EC 2.5.1.21). Squalene synthase catalyzes the formation of squalene from trans-farnesyl diphosphate in two distinct steps and is the first committed enzyme for the biosynthesis of cholesterol. Recently, a truncated form of the enzyme from rat hepatocytes was purified, and monospecific antibodies for squalene synthase were produced. This enabled the subcellular localization of squalene synthase by three different methods: (i) analytical subcellular fractionation and measurements of enzyme activities; (ii) immunodeterminations of squalene synthase in the isolated subcellular fractions with a monospecific antibody; and (iii) immunoelectron microscopy. All three methods gave consistent results. The data clearly illustrate that squalene synthase enzymatic activity and squalene synthase are exclusively localized in the endoplasmic reticulum. In rat hepatic peroxisomes we were not able to detect any squalene synthase. In addition, we also demonstrated that squalene synthase in the microsomal fraction is dramatically regulated by a number of hypolipidemic drugs and dietary treatments.
