Tipper J P, Bacon G W, Witters L A
Arch Biochem Biophys. 1983 Dec;227(2):386-96. doi: 10.1016/0003-9861(83)90468-x.
Two cAMP-independent acetyl-CoA carboxylase (ACC) protein kinases have been partially purified from rat liver cytosol and microsomal extracts. The first kinase, present in greatest activity in microsomal extracts, appears to be identical to casein kinase I by characteristic molecular size on gel filtration (Mr 40,000) and sodium dodecyl sulfate-gel electrophoresis (Mr 34,000), autophosphorylation of this single subunit, inability to efficiently utilize GTP, and resistance to inhibition by heparin and 2,3-diphosphoglycerate. The second kinase, predominant in cytosol, appears to be identical to casein kinase II by characteristic molecular size on gel filtration (Mr 150,000), an autophosphorylated subunit of Mr 25,000, a Km for GTP nearly equal to that of ATP, inhibition by heparin and 2,3 DPG, and relative substrate specificity. Despite the incorporation of up to 2 mol 32P/mol carboxylase subunit (kinase I) and 0.6 mol/subunit (kinase II), phosphorylation by either kinase causes no change in carboxylase activity. The site(s) phosphorylated by each kinase and by the cAMP-dependent protein kinase on carboxylase appear to be clustered on a Mr 16,000 cyanogen bromide peptide that is readily released on incubation with trypsin. The potential roles of these kinases in the regulation of ACC remain to be clarified.
已从大鼠肝脏胞质溶胶和微粒体提取物中部分纯化出两种不依赖环磷酸腺苷（cAMP）的乙酰辅酶A羧化酶（ACC）蛋白激酶。第一种激酶在微粒体提取物中的活性最高，通过凝胶过滤（分子量40,000）和十二烷基硫酸钠-凝胶电泳（分子量34,000）的特征性分子大小、该单亚基的自磷酸化、无法有效利用鸟苷三磷酸（GTP）以及对肝素和2,3-二磷酸甘油酸抑制的抗性，它似乎与酪蛋白激酶I相同。第二种激酶在胞质溶胶中占主导，通过凝胶过滤（分子量150,000）的特征性分子大小、分子量25,000的自磷酸化亚基、GTP的米氏常数（Km）几乎与三磷酸腺苷（ATP）相等、受肝素和2,3-二磷酸甘油酸（2,3 DPG）抑制以及相对底物特异性，它似乎与酪蛋白激酶II相同。尽管每摩尔羧化酶亚基（激酶I）可掺入多达2摩尔的32P，每亚基（激酶II）可掺入0.6摩尔，但任何一种激酶的磷酸化都不会导致羧化酶活性发生变化。每种激酶以及cAMP依赖性蛋白激酶在羧化酶上磷酸化的位点似乎聚集在一个分子量16,000的溴化氰肽上，该肽在与胰蛋白酶孵育时很容易释放出来。这些激酶在ACC调节中的潜在作用仍有待阐明。
