Synthesis of pyrophosphate coupled to the reverse energy‐linked transhydrogenase reaction in Rhodospirillum rubrum chromatophores

FEBS Letters

Nore, Beston F.¹  Husain, Iqbal¹  Nyrén, Pål¹  Baltscheffsky, Margareta¹ 

[1] Department of Biochemistry, Arrhenius Laboratory, University of Stockholm, S-106 91 Stockholm, Sweden

关键词: (Rhodospirillum rubrum) Energy-linked transhydrogenase Pyrophosphate synthesis ATP synthesis Bioluminescence;    APS;    adenosine 5 '-phosphosulphate;    Bchl;    bacteriochlorophyll;    BSA;    bovine serum albumin;    DAPP;    diadenosine pentaphosphate (Ap5A);    DCCD;    N;    N'-dicyclohexylcarbodiimide;    DTE;    1;    4-dithioerythritol;    FCCP;    carbonyl cyanide p-trifluoromethoxyhydrazone;    PCB−;    phenyl dicarbaundecarborane;    ANS;    8-anilinonaphthalene-1-sulphonic acid;    H−-PPase;    H−pyrophosphatase;    H+ATPase;    H+-ATP Synthase;   

DOI  :  10.1016/0014-5793(86)80525-7

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Chromatophores from the photosynthetic bacterium Rhodospirillum rubrum contain a membrane-bound transhydrogenase catalyzing the transfer of a hydride ion between NADH and NADP⁺. The reverse reaction, i.e. reduction of NAD⁺ by NADPH, can furnish sufficient energy (ΔgmH⁺) to drive the phosphorylation of inorganic orthophosphate (P_i) to pyrophosphate (PP_i). The rate of pp_i synthesis is 50 nmol PP_i formed/min per μmol Bchl which is 5% of the rate of light-induced PP_i synthesis. PP_i synthesis is inhibited by both the H⁺-PPase inhibitor fluoride and the specific transhydrogenase inhibitor palmitoyl-CoA. The effects of both DCCD and uncouplers on the system provide additional evidence that the ΔgmH⁺ generated by the reverse transhydrogenase reaction drives PP_i synthesis. The rate of PP_i synthesis can be partially inhibited by the addition of NADP⁺ a substrate of the forward energy-consuming reaction. The ΔgmH⁺ generated can also be used to drive ATP synthesis by the H⁺-ATPase, but at a lower rate than the pp_i synthesis.

【 授权许可】

Unknown