Guerra D J, Ohlrogge J B
Arch Biochem Biophys. 1986 Apr;246(1):274-85. doi: 10.1016/0003-9861(86)90473-x.
Investigation of malonyl-CoA:acyl carrier protein transacylase from soybeans has shown that this fatty acid biosynthetic enzyme occurs in at least two isozymic forms. Both forms exist as soluble, low-molecular-mass polypeptides (approx 43 kDa) which catalyze one of the first committed steps in the synthesis of C16 and C18 fatty acids. We have partially purified the two forms of this enzyme from soybean leaf tissue 1200- and 3900-fold respectively. Isozyme 1 does not adhere to ion-exchange or blue dye affinity chromatographic supports and elutes from a polybuffer exchanger column at a pH of 7.3. Isozyme 2 requires salt to be eluted from ion-exchange and affinity matrices and elutes from a polybuffer exchanger column at a pH of 5.3. The two forms of malonyl-CoA:acyl carrier protein transacylase also differ in their sensitivity to catalytic inhibitors, heat treatment, and inhibition by acyl-CoA ester substrates. Both forms utilize malonyl-CoA as the preferred substrate, and polyacrylamide gel electrophoresis of reaction products indicated that malonyl-acyl carrier protein was the major product formed. Analysis of developing soybean seeds indicates that only one form (isozyme 1) is predominant, whereas leaf tissue possesses both isozymes.
对大豆丙二酰辅酶A：酰基载体蛋白转酰基酶的研究表明，这种脂肪酸生物合成酶至少以两种同工酶形式存在。两种形式均以可溶性低分子量多肽（约43 kDa）存在，它们催化C16和C18脂肪酸合成中最早的关键步骤之一。我们已分别从大豆叶片组织中对这两种形式的酶进行了部分纯化，纯化倍数分别为1200倍和3900倍。同工酶1不附着于离子交换或蓝色染料亲和色谱支持物，在pH 7.3时从多缓冲交换柱上洗脱。同工酶2需要盐才能从离子交换和亲和基质上洗脱，在pH 5.3时从多缓冲交换柱上洗脱。丙二酰辅酶A：酰基载体蛋白转酰基酶的两种形式对催化抑制剂、热处理和酰基辅酶A酯底物抑制的敏感性也有所不同。两种形式均以丙二酰辅酶A作为首选底物，反应产物的聚丙烯酰胺凝胶电泳表明丙二酰-酰基载体蛋白是形成的主要产物。对发育中的大豆种子的分析表明，只有一种形式（同工酶1）占主导地位，而叶片组织中两种同工酶都有。
