Alhomida A S, Duhaiman A S, al-Jafari A A, Junaid M A
Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia.
Mol Cell Biochem. 1996 Dec 20;165(2):95-101. doi: 10.1007/BF00229470.
The enzyme carnitine acetyltransferase (CAT) catalyzes the reversible transfer of short-chain acyl groups between coenzyme A and L-carnitine, and hence, plays an important role in the beta-oxidation of fatty acids. Purification and characterization of CAT from desert animal species may help in explaining the involvement of secondary pathways for energy production in these species. In this paper, we report the purification and partial characterization of CAT from the Arabian camel. CAT was purified from the skeletal muscle of the Arabian camel by ammonium sulfate and acetone fractionation, followed by chromatography on DEAE-Sepharose, agarose-Co A and Superose 12 gel filtration columns. CAT was purified by 2937-fold to a specific activity of 94 Units mg-1. The purified CAT was a monomer of 59 kDa as judged by native and SDS-PAGE, and showed a pI of 5.2. The enzyme displayed maximum activity with propionyl-Co A. Apparent Km for acetyl-, propionyl- and butyryl-Co A were 27.7, 17.3 and 29 microM respectively, while palmitoyl-Co A was not a substrate.
肉碱乙酰转移酶（CAT）催化辅酶A与L-肉碱之间短链酰基的可逆转移，因此在脂肪酸的β氧化中起重要作用。从沙漠动物物种中纯化和鉴定CAT可能有助于解释这些物种中能量产生的次要途径的参与情况。在本文中，我们报告了从阿拉伯骆驼中纯化和部分鉴定CAT的情况。通过硫酸铵和丙酮分级分离，然后在DEAE-琼脂糖、琼脂糖-Co A和Superose 12凝胶过滤柱上进行层析，从阿拉伯骆驼的骨骼肌中纯化出CAT。CAT纯化了2937倍，比活性为94单位mg-1。通过天然和SDS-PAGE判断，纯化的CAT是一个59 kDa的单体，pI为5.2。该酶对丙酰辅酶A表现出最大活性。乙酰辅酶A、丙酰辅酶A和丁酰辅酶A的表观Km分别为27.7、17.3和29 microM，而棕榈酰辅酶A不是底物。
