Fuller S J, Randle P J
Biochem J. 1984 Apr 15;219(2):635-46. doi: 10.1042/bj2190635.
The total activity of pyruvate dehydrogenase (PDH) complex in rat hind-limb muscle mitochondria was 76.4 units/g of mitochondrial protein. The proportion of complex in the active form was 34% (as isolated), 8-14% (incubation with respiratory substrates) and greater than 98% (incubation without respiratory substrates). Complex was also inactivated by ATP in the presence of oligomycin B and carbonyl cyanide m-chlorophenylhydrazone. Ca2+ (which activates PDH phosphatase) and pyruvate or dichloroacetate (which inhibit PDH kinase) each increased the concentration of active PDH complex in a concentration-dependent manner in mitochondria oxidizing 2-oxoglutarate/L-malate. Values giving half-maximal activation were 10 nM-Ca2+, 3 mM-pyruvate and 16 microM-dichloroacetate. Activation by Ca2+ was inhibited by Na+ and Mg2+. Mitochondria incubated with [32P]Pi/2-oxoglutarate/L-malate incorporated 32P into three phosphorylation sites in the alpha-chain of PDH; relative rates of phosphorylation were sites 1 greater than 2 greater than 3, and of dephosphorylation, sites 2 greater than 1 greater than 3. Starvation ( 48h ) or induction of alloxan-diabetes had no effect on the total activity of PDH complex in skeletal-muscle mitochondria, but each decreased the concentration of active complex in mitochondria oxidizing 2-oxoglutarate/L-malate and increased the concentrations of Ca2+, pyruvate or dichloracetate required for half-maximal reactivation. In extracts of mitochondria the activity of PDH kinase was increased 2-3-fold by 48 h starvation or alloxan-diabetes, but the activity of PDH phosphatase was unchanged.
大鼠后肢肌肉线粒体中丙酮酸脱氢酶（PDH）复合体的总活性为76.4单位/克线粒体蛋白。复合体以活性形式存在的比例为34%（分离状态）、8 - 14%（与呼吸底物一起孵育）和大于98%（无呼吸底物孵育）。在寡霉素B和羰基氰化物间氯苯腙存在的情况下，ATP也会使复合体失活。Ca²⁺（激活PDH磷酸酶）、丙酮酸或二氯乙酸（抑制PDH激酶）在氧化2 - 酮戊二酸/L - 苹果酸的线粒体中，均以浓度依赖的方式增加活性PDH复合体的浓度。产生半数最大激活作用的值分别为：Ca²⁺为10 nM、丙酮酸为3 mM、二氯乙酸为16 μM。Ca²⁺的激活作用受到Na⁺和Mg²⁺的抑制。用[³²P]Pi/2 - 酮戊二酸/L - 苹果酸孵育的线粒体将³²P掺入到PDH α链的三个磷酸化位点；磷酸化的相对速率为位点1＞位点2＞位点3，去磷酸化的相对速率为位点2＞位点1＞位点3。饥饿（48小时）或诱导四氧嘧啶糖尿病对骨骼肌线粒体中PDH复合体的总活性没有影响，但二者均降低了氧化2 - 酮戊二酸/L - 苹果酸的线粒体中活性复合体的浓度，并增加了产生半数最大再激活所需的Ca²⁺、丙酮酸或二氯乙酸的浓度。在饥饿48小时或四氧嘧啶糖尿病诱导后，线粒体提取物中PDH激酶的活性增加了2 - 3倍，但PDH磷酸酶的活性未发生变化。
