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- Title
Zinc ions selectively inhibit steps associated with binding and release of NADP(H) during turnover of proton-translocating transhydrogenase
- Authors
Whitehead, Simon J.; Rossington, Karen E.; Hafiz, Abdul; Cotton, Nick P.J.; Jackson, J. Baz
- Abstract
Abstract: Transhydrogenase couples the redox reaction between NAD(H) and NADP(H) to proton translocation across a membrane. In membrane vesicles from Escherichia coli and Rhodospirillum rubrum, the transhydrogenase reaction (measured in the direction driving inward proton translocation) was inhibited by Zn2+ and Cd2+. However, depending on pH, the metal ions either had no effect on, or stimulated, “cyclic” transhydrogenation. They must, therefore, interfere specifically with steps involving binding/release of NADP+/NADPH: the steps thought to be associated with proton translocation. It is suggested that Zn2+ and Cd2+ bind in the proton-transfer pathway and block inter-conversion of states responsible for changing NADP+/NADPH binding energy.
- Subjects
INTERMEDIATES (Chemistry); PROPERTIES of matter; PROTEINS; ESCHERICHIA
- Publication
FEBS Letters, 2005, Vol 579, Issue 13, p2863
- ISSN
0014-5793
- Publication type
Article
- DOI
10.1016/j.febslet.2005.04.026