Oxygen exchange reactions catalyzed by vacuolar H+‐translocating pyrophosphatase Evidence for reversible formation of enzyme‐bound pyrophosphate

FEBS Letters

Rea, Philip A.⁴  Kasho, Vladimir N.³  Baykov, Alexander A.¹  Bakuleva, Natalia P.² 

[1] A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119899, Russian Federation;A.N. Bakulev Institute of Cardiovascular Surgery, Academy of Medical Sciences, Moscow 117049, Russian Federation;Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90024, USA;Plant Science Institute, Department of Biology, University of Pennsylvania, Philadelphia, PA 19104-6018, USA

关键词: Inorganic pyrophosphatase;    Oxygen exchange;    Phosphate;    Proton pump;    Pyrophosphate;    Vacuolar membrane;    PPase;    inorganic pyrophosphatase;    Pi;    pyrophosphate;    PPi;    phosphate;    V-ATPase;    vacuolar H+-ATPase;    V-PPase;    vacuolar H+-pyrophosphatase;   

DOI  :  10.1016/0014-5793(94)00800-0

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Vacuolar membrane-derived vesicles isolated from Vigna radiata catalyze oxygen exchange between medium phosphate and water. On the basis of the inhibitor sensitivity and cation requirements of the exchange activity, it is almost exclusively attributable to the vacuolar H⁺-pyrophosphatase (V-PPase). The invariance of the partition coefficient and the results of kinetic modeling indicate that exchange proceeds via a single reaction pathway and results from the reversal of enzyme-bound pyrophosphate synthesis. Comparison of the exchange reactions catalyzed by V-PPase and soluble PPases suggests that the two classes of enzyme mediate P_i–HOH exchange by the same mechanism and that the intrinsic reversibility of the V-PPase is no greater than that of soluble PPases.

【 授权许可】

Unknown