FEBS Letters | |
On the rate of F1‐ATPase turnover during ATP hydrolysis by the single catalytic site Evidence that hydrolysis with a slow rate of product release does not occur at the alternating active site | |
Milgrom, Ya.M.1  Murataliev, M.B.1  | |
[1] A.N. Belozersky Laboratory of Molecular Biology and Bioorganic Chemistry, Moscow State University 119899 Moscow, USSR | |
关键词: F1-ATPase; Single-site catalysis; Turnover rate; | |
DOI : 10.1016/0014-5793(87)80186-2 | |
学科分类:生物化学/生物物理 | |
来源: John Wiley & Sons Ltd. | |
【 摘 要 】
Under conditions of molar excess of enzyme, isolated F1-ATPase from beef heart mitochondria catalyses ATP hydrolysis biphasically. The rate constants for product release are ∼10−1 and 10−4−10−3 s−1, respectively. The slow phase of ATP hydrolysis is insensitive to EDTA. [γ-32P]ATP splitting in the slow phase cannot be chased from the enzyme during several catalytic turnovers. It follows from these results that the slow single-site hydrolysis of ATP (k cat∼10−4s−1), initially observed by Grubmeyer et al. [(1982) J. Biol. Chem. 257, 12092–12100], is not carried out by the normal catalytic site. In contrast, the phase of rapid ATP hydrolysis (k cat∼10−1s−1) is completely prevented by EDTA and is believed to be the normal function of the normal catalytic site of F1-ATPase.
【 授权许可】
Unknown
【 预 览 】
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