Behrends W, Engeland K, Kindl H
Universität Marburg, Federal Republic of Germany.
Arch Biochem Biophys. 1988 May 15;263(1):161-9. doi: 10.1016/0003-9861(88)90624-8.
The enzymatic apparatus of fatty acid beta-oxidation in peroxisomes and glyoxysomes includes a multifunctional protein. Two forms of this protein were detected in extracts from cotyledons of germinating cucumber seeds and separated on hydroxylapatite. The two proteins purified to apparent homogeneity possessed enoyl-CoA hydratase, 3-hydroxyacyl-CoA epimerase, and 3-hydroxyacyl-CoA dehydrogenase activity; the proteins are therefore trifunctional. Analysis of molecular structures and kinetic parameters of the two enzyme forms revealed significant differences in size and amino acid composition. The two proteins were characterized as monomers exhibiting molecular weights of 74,000 and 76,500. Likewise, the data obtained with limited proteolysis proved the occurrence of two independent proteins. Immunological comparisons were performed with antibodies raised against the 76.5-kDa protein. They indicated a weak relationship between the two proteins. From that we conclude that within one type of organelle, i.e., glyoxysome, two isoenzymes with multiple functions are located.
过氧化物酶体和乙醛酸循环体中脂肪酸β-氧化的酶系包括一种多功能蛋白。在发芽黄瓜种子子叶的提取物中检测到该蛋白的两种形式，并在羟基磷灰石上进行了分离。纯化至表观均一的这两种蛋白具有烯酰辅酶A水合酶、3-羟酰基辅酶A表异构酶和3-羟酰基辅酶A脱氢酶活性；因此，这些蛋白是三功能的。对这两种酶形式的分子结构和动力学参数分析表明，它们在大小和氨基酸组成上存在显著差异。这两种蛋白被表征为分子量分别为74,000和76,500的单体。同样，有限蛋白酶解实验的数据证明存在两种独立的蛋白。用针对76.5 kDa蛋白产生的抗体进行了免疫比较。结果表明这两种蛋白之间存在微弱的关系。由此我们得出结论，在一种细胞器即乙醛酸循环体中，存在两种具有多种功能的同工酶。
