Borthwick A C, Edgell N J, Denton R M
Biochem J. 1987 Feb 1;241(3):773-82. doi: 10.1042/bj2410773.
Superose 6 chromatography was used to separate rapidly the polymeric and dimeric forms of acetyl-CoA carboxylase. With preparations of acetyl-CoA carboxylase purified by Sepharose-avidin chromatography, it is shown that citrate promotes polymerization and that the extent of polymerization is diminished, but not eliminated, after phosphorylation by cyclic-AMP-dependent protein kinase. After exposure of rat epididymal adipose tissue to insulin, evidence was obtained for a marked increase in polymerization. The polymeric form, which was active in the absence of citrate, exhibited increased phosphorylation, particularly on a tryptic peptide designated the I-peptide in an earlier study [Brownsey & Denton (1982) Biochem. J. 202, 77-86]. In contrast, in tissue exposed to the beta-agonist isoprenaline, most of the phosphorylated acetyl-CoA carboxylase appeared to be in the dimeric form if chromatography was carried out in the absence of citrate, whereas in the presence of citrate the degree of polymerization was diminished.
使用Superose 6色谱法快速分离乙酰辅酶A羧化酶的聚合形式和二聚体形式。用通过琼脂糖抗生物素蛋白色谱法纯化的乙酰辅酶A羧化酶制剂表明,柠檬酸促进聚合作用,并且在由环磷酸腺苷依赖性蛋白激酶磷酸化后,聚合程度降低但未消除。将大鼠附睾脂肪组织暴露于胰岛素后,有证据表明聚合作用显著增加。在没有柠檬酸的情况下具有活性的聚合形式表现出磷酸化增加,特别是在早期研究[Brownsey和Denton(1982年)《生物化学杂志》202, 77 - 86]中指定为I - 肽的胰蛋白酶肽上。相反,在暴露于β - 激动剂异丙肾上腺素的组织中,如果在没有柠檬酸的情况下进行色谱分析,大多数磷酸化的乙酰辅酶A羧化酶似乎以二聚体形式存在,而在有柠檬酸的情况下,聚合程度降低。