Paynter K T, Karam G A, Ellis L L, Bishop S H
J Exp Zool. 1985 Dec;236(3):251-7. doi: 10.1002/jez.1402360302.
The pyruvate dehydrogenase complex has been demonstrated in high speed pellet preparations from sonicated ribbed mussel gill mitochondria. The activity of the complex is inhibited by low chloride (less than 100 mM) concentrations, EDTA (1 mM), succinate, ATP, and NAD/NADH ratios below 4. Inhibition by EDTA is relieved by addition of 10 mM MgCl2-1 mM CaCl2. ATP inhibition was enhanced by NaF and reversed by high Mg++ concentrations in the absence of NaF. Pyruvate and thiamine pyrophosphate inhibited the inactivation by ATP. The nonhydrolyzable ATP analog AMP-PNP caused inhibition of the overall catalytic activity that was identical to ATP. Factors involved in the ATP inhibition and Mg++ reversal are lost with freezing or cold storage. Preliminary results using gamma-32P-ATP indicate that a protein kinase that phosphorylates the alpha subunit of E1 (pyruvate dehydrogenase) from the mammalian PDC is associated with the gill PDC. The activity of the complex may be regulated by a phosphorylation/dephosphorylation mechanism and by the relative levels of substrates, products, and other metabolites in the mitochondria.
丙酮酸脱氢酶复合体已在超声处理的肋贻贝鳃线粒体高速沉淀制剂中得到证实。该复合体的活性受到低氯（低于100 mM）浓度、EDTA（1 mM）、琥珀酸、ATP以及低于4的NAD/NADH比值的抑制。添加10 mM MgCl₂ - 1 mM CaCl₂可解除EDTA的抑制作用。在不存在NaF的情况下，NaF会增强ATP的抑制作用，而高浓度的Mg²⁺可逆转这种抑制作用。丙酮酸和硫胺焦磷酸可抑制ATP导致的失活。不可水解的ATP类似物AMP - PNP对整体催化活性的抑制作用与ATP相同。与ATP抑制和Mg²⁺逆转相关的因子会因冷冻或冷藏而丧失。使用γ - ³²P - ATP的初步结果表明，一种可使哺乳动物丙酮酸脱氢酶复合体中E1（丙酮酸脱氢酶）的α亚基磷酸化的蛋白激酶与鳃丙酮酸脱氢酶复合体相关。该复合体的活性可能受磷酸化/去磷酸化机制以及线粒体中底物、产物和其他代谢物的相对水平调控。
