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Mitochondrial Nucleoside Diphosphate Kinase: Mode of Interaction with the Outer Mitochondrial Membrane and Proportion of Catalytic Activity Functionally Coupled to Oxidative Phosphorylation

T. Yu. Lipskaya* and V. V. Voinova

Department of Biochemistry, Faculty of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; fax: (495) 939-3955; E-mail: tlipskaya@yandex.ru

* To whom correspondence should be addressed.

Received June 13, 2007; Revision received September 24, 2007
In the present study, we found that ionic interactions are not essential for the binding of nucleoside diphosphate kinase of liver mitochondria outer compartment to outer mitochondrial membrane and that the proportion of the enzyme activity involved in functional coupling with oxidative phosphorylation (we demonstrated the existence of functional coupling earlier) is only 17%. Additional evidence was obtained that functionally coupled activity of nucleoside diphosphate kinase is associated with the outer surface of mitochondria. Dextran (10%) did not increase functional coupling. The physiological importance of these effects is discussed.
KEY WORDS: nucleoside diphosphate kinase, mitochondria, outer compartment, localization, oxidative phosphorylation, functional coupling

DOI: 10.1134/S0006297908030139