Journal of Bioenergetics and Biomembranes

, Volume 23, Issue 5, pp 715–741

The proton-translocating nicotinamide adenine dinucleotide transhydrogenase

  • J. B. Jackson
Mini-Review

DOI: 10.1007/BF00785998

Cite this article as:
Jackson, J.B. J Bioenerg Biomembr (1991) 23: 715. doi:10.1007/BF00785998

Abstract

H+-transhydrogenase couples the reversible transfer of hydride ion equivalents between NAD(H) and NADP(H) to the translocation of protons across a membrane. There are separate sites on the enzyme for the binding of NAD(H) and of NADP(H). There are some indications of the position of the binding sites in the primary sequence of the enzymes from mitochondria andEscherichia coli. Transfer of hydride ion equivalents only proceeds when a reduced and an oxidized nucleotide are simultaneously bound to the enzyme. When Δp=0 the rate of interconversion of the ternary complexes of enzyme and nucleotide substrates is probably limiting. An increase in Δp accelerates the rate of interconversion in the direction of NADH → NADP+ until another kinetic component, possibly product release, becomes limiting. The available data are consistent with either direct or indirect mechanisms of energy coupling.

Key words

Transhydrogenaseprotonmotive forceproton translocationenergy coupling

Abbreviations

DCCD

N N1-dicyclohexylcarbodiimide

FSBA

51-[p-(fluorosulfonyl)benzoyl] adenosine

FCCP

carbonylcyanide-p-fluoromethoxyphenylhydrazone

H+-Thase

H+-transhydrogenase

thio-NADP+

thionicotinamide adenine dinucleotide phosphate

AcPdAd+

3-acetylpyridine adenine dinucleotide

Δp

proton electrochemical gradient

Δψ

membane potential

ΔpH

pH difference across the membrane

Copyright information

© Plenum Publishing Corporation 1991

Authors and Affiliations

  • J. B. Jackson
    • 1
  1. 1.School of BiochemistryUniversity of BirminghamBirminghamU.K.