pATP citrate lyase is shown to exist as multiple forms in extracts of rat liver. DEAE-Sephadex ion-exchange chromatography of liver supernatants reveals two peaks of activity. A minor, basic, component, comprising 14% of the recovered activity, is eluted without retention, whereas the major, acidic, form is eluted by a KCl gradient. Gel filtration of similar extracts shows the presence of a high-Mr form of ATP citrate lyase (Mr around 10(7) in addition to the tetrameric enzyme (Mr 4.1 X 10(5). This associated state, which represents 10% of the total activity, is unstable, breaking down to the tetramer, and appears to be disrupted by Mg2+. The basic form changes in the partially purified state to give the acidic form. Most of the high-Mr enzyme is acidic in nature. No evidence could be found for an association of the enzyme with mitochondrial or microsomal membranes. ATP citrate lyase from rat brain also shows two peaks of activity on DEAE-Sephadex ion-exchange chromatography, but the activity is distributed between the peaks in almost equal proportions. However, only the tetrameric enzyme was observed on gel filtration./p
展开▼
机译：ATP柠檬酸裂合酶在大鼠肝脏提取物中显示为多种形式。肝脏上清液的DEAE-Sephadex离子交换色谱法显示出两个活性峰。少量的碱性成分（占所回收活性的14％）被洗脱而没有保留，而主要的酸性形式被KCl梯度洗脱。相似提取物的凝胶过滤显示，除了四聚酶（Mr 4.1 X 10（5）之外，还存在高Mr形式的ATP柠檬酸裂解酶（Mr在10（7）左右）。这种缔合状态代表了10％的总活性不稳定，分解成四聚体，似乎被Mg2 +破坏，基本形式改变为部分纯化状态，变成酸性形式，大多数高Mr酶本质上是酸性的，没有证据可以证明还发现这种酶与线粒体或微粒体膜有关，来自大鼠脑的ATP柠檬酸裂合酶在DEAE-Sephadex离子交换色谱上也显示出两个活性峰，但活性几乎以相等的比例分布在两个峰之间。凝胶过滤仅观察到四聚酶。
展开▼
