Prasanna P, Holmlund C E
Int J Biochem. 1987;19(4):385-9. doi: 10.1016/0020-711x(87)90013-9.
The major HMG-CoA utilizing enzyme activity in T. pyriformis has been determined to be HMG-CoA lyase. The enzyme was purified 32-fold to a specific activity of 431 units/mg from a mitochondrial fraction. Sephacryl S-200 chromatography gave an estimated molecular weight of 50,000 daltons for the HMG-CoA lyase. SDS gel electrophoresis revealed two bands stained by Coomassie Blue--a major band of 50,000 daltons and a minor band of 25,000 daltons. The latter is believed to be an impurity in the preparation. The enzyme has a pH optimum of 9.0, is stimulated slightly by sulfhydryl reagents, and requires a divalent cation for maximum activity. The KM for HMG-CoA is 15 microM.
已确定梨形四膜虫中利用HMG-CoA的主要酶活性是HMG-CoA裂解酶。该酶从线粒体部分纯化了32倍，比活性达到431单位/毫克。Sephacryl S-200色谱法测得HMG-CoA裂解酶的估计分子量为50,000道尔顿。SDS凝胶电泳显示两条经考马斯亮蓝染色的条带——一条主要的50,000道尔顿条带和一条次要的25,000道尔顿条带。后者被认为是制备过程中的杂质。该酶的最适pH为9.0，受到巯基试剂的轻微刺激，并且需要二价阳离子才能达到最大活性。HMG-CoA的米氏常数为15微摩尔。
