Dipartimento di Scienze per la Salute, Università del Molise, via De Sanctis-86100 Campobasso, Italy.
Arch Biochem Biophys. 2010 Mar 1;495(1):42-8. doi: 10.1016/j.abb.2009.12.016. Epub 2009 Dec 21.
The existence of the pyruvate kinase (PK) in pig liver mitochondria was shown by monitoring photometrically the PK reaction in solubilised mitochondria with either phosphoenolpyruvate (PEP) or ADP used as a substrate. In distinction with the cytosolic isoenzyme, the mitochondrial PK showed a sigmoidal dependence on either PEP or ADP concentrations. The occurrence of the mitochondrial PK was confirmed by immunological analysis. Titration with digitonin showed that mPK is restricted to the matrix. PEP addition to mitochondria resulted in reduction of the intramitochondrial NAD(P)+ inhibited by either the non-penetrant thiol reagent mersalyl or by arsenite, an inhibitor of the pyruvate dehydrogenase complex. Citrate/oxaloacetate appearance outside mitochondria also occurred as result of PEP addition to PLM. Taken together these findings support a role for PEP itself in triggering fatty acid synthesis via its mitochondrial metabolism.
已证明猪肝线粒体中存在丙酮酸激酶 (PK)，通过监测用磷酸烯醇丙酮酸 (PEP) 或 ADP 作为底物溶解的线粒体中的 PK 反应，可对其进行分光光度法检测。与胞质同工酶不同，线粒体 PK 对 PEP 或 ADP 浓度的依赖性呈 S 形。通过免疫学分析证实了线粒体 PK 的存在。用去氧胆酸钠滴定表明 mPK 仅限于基质。向线粒体中添加 PEP 会导致 NAD(P)+ 的减少，这可被非渗透硫醇试剂 mersalyl 或丙酮酸脱氢酶复合物的抑制剂亚砷酸盐抑制。由于 PEP 加入 PLM，柠檬酸/草酰乙酸也会出现在线粒体之外。这些发现共同支持 PEP 本身通过其线粒体代谢触发脂肪酸合成的作用。
