Ngo T T, Barbeau A
Can J Neurol Sci. 1978 Feb;5(1):105-9.
The Pyruvate dehydrogenase multienzyme complex (PDHC) purified from rat brain is phosphorylated in the presence of low concentrations of ATP and MgCl2. The phosphorylated PDHC is incapable of catalyzing the oxidative decarboxylation of pyruvate. In the presence of high concentrations (10 mM) of MgCl2, the phosphorylated (inactive) PDHC is converted back to the dephospho-form of PDHC which is catalytically active. The dihydrolipoyl dehydrogenase (LAD) component, E3, of PDHC is inactivated by pyridoxal phosphate (PLP) and the PLP-inactivated LAD can be reactivated by an amino acid, taurine. These results indicate the reversible formation of Schiff base between PLP and LAD. They also provide clear evidence for the involvement of LAD (E3) in the previously reported inactivation of PDHC by PLP.
从大鼠脑中纯化的丙酮酸脱氢酶多酶复合物（PDHC）在低浓度ATP和MgCl2存在的情况下会发生磷酸化。磷酸化的PDHC无法催化丙酮酸的氧化脱羧反应。在高浓度（10 mM）MgCl2存在的情况下，磷酸化（无活性）的PDHC会转化回具有催化活性的去磷酸化形式的PDHC。PDHC的二氢硫辛酰胺脱氢酶（LAD）组分E3会被磷酸吡哆醛（PLP）灭活，而被PLP灭活的LAD可以被一种氨基酸——牛磺酸重新激活。这些结果表明PLP与LAD之间可逆地形成了席夫碱。它们还为LAD（E3）参与先前报道的PLP对PDHC的灭活作用提供了明确的证据。
