Regulatory function of protein X, a component of the pyruvate dehydrogenase complex
Selivanov, V.A.; Gol'dshtein, B.N.; Khailova, L.S.
Molekulyarnaya Biologiya 27(5): 1070-1077
The regulatory role of protein X, a component of the pyruvate dehydrogenase complex, is investigated. A kinetic model, based on the data available in the literature concerning the structural-functional relations between protein X and other components of the complex, is developed. Computer analysis of the model shows the critical role of protein X in the functioning and regulation of the complex. Owing to protein X, there are two reaction pathways catalyzed by the complex, and the ratio of acetylated/deacetylated protein X determines the operative pathway. When the concentration of substrate (pyruvate) is increased, the reaction is switched to the pathway for which the rate is independent of the substrate level. The importance of the new type of regulation revealed for the stabilization of energy metabolism is discussed.