Schnitzer-Polokoff R, Sinensky M
Eleanor Roosevelt Institute for Cancer Research, Denver, Colorado 80262.
J Cell Biochem. 1987 Oct;35(2):93-103. doi: 10.1002/jcb.240350203.
This report describes the characterization and partial purification of rat liver 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) synthase activity. A preliminary characterization of Chinese hamster ovary (CHO) cell HMG CoA synthase activity is also presented. Ion-exchange chromatography of ammonium sulfate precipitates of rat liver cytosol indicate the existence of two isoenzymes of HMG CoA synthase. These isoenzymes are physically, catalytically, and immunologically distinct. One of these isoenzymes, peak 1, resembles mitochondrial HMG-CoA synthase activity as evidenced by similarities in elution upon ion-exchange chromatography, inhibition by MgCl2, and cross reactivity with an antibody prepared against the mitochondrial enzyme. As peak 1 activity is unstable, further purification studies were performed on peak 2 activity. Peak 2 can be further resolved into two activities (peaks 2A and 2B) by gel filtration. In contrast, CHO-K1 cells (a permanent fibroblast line) possess only peak 2 type HMG CoA synthase activity.
本报告描述了大鼠肝脏3-羟基-3-甲基戊二酰辅酶A（HMG CoA）合酶活性的特性及部分纯化过程。同时也介绍了中国仓鼠卵巢（CHO）细胞HMG CoA合酶活性的初步特性。对大鼠肝脏胞质溶胶硫酸铵沉淀物进行离子交换层析表明存在两种HMG CoA合酶同工酶。这些同工酶在物理性质、催化活性和免疫特性上均有差异。其中一种同工酶，峰1，类似于线粒体HMG-CoA合酶活性，这一点通过离子交换层析洗脱时的相似性、MgCl2的抑制作用以及与针对线粒体酶制备的抗体的交叉反应得以证明。由于峰1活性不稳定，因此对峰2活性进行了进一步的纯化研究。通过凝胶过滤，峰2可进一步分解为两种活性（峰2A和峰2B）。相比之下，CHO-K1细胞（一种永久性成纤维细胞系）仅具有峰2型HMG CoA合酶活性。
