کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1943693 | 1537056 | 2006 | 7 صفحه PDF | دانلود رایگان |

Fo·F1-ATP synthase in inside-out coupled vesicles derived from Paracoccus denitrificans catalyzes Pi-dependent proton-translocating ATPase reaction if exposed to prior energization that relieves ADP·Mg2+-induced inhibition (Zharova, T.V. and Vinogradov, A.D. (2004) J. Biol. Chem.,279, 12319–12324). Here we present evidence that the presence of medium ADP is required for the steady-state energetically self-sustained coupled ATP hydrolysis. The initial rapid ATPase activity is declined to a certain level if the reaction proceeds in the presence of the ADP-consuming, ATP-regenerating system (pyruvate kinase/phosphoenol pyruvate). The rate and extent of the enzyme de-activation are inversely proportional to the steady-state ADP concentration, which is altered by various amounts of pyruvate kinase at constant ATPase level. The half-maximal rate of stationary ATP hydrolysis is reached at an ADP concentration of 8 × 10−6 M. The kinetic scheme is proposed explaining the requirement of the reaction products (ADP and Pi), the substrates of ATP synthesis, in the medium for proton-translocating ATP hydrolysis by P. denitrificans Fo·F1-ATP synthase.
Journal: Biochimica et Biophysica Acta (BBA) - Bioenergetics - Volume 1757, Issues 5–6, May–June 2006, Pages 304–310