The unusual transhydrogenase of Entamoeba histolytica

[摘要]

We have expressed and purified a protein fragment from Entamoeba histolytica. It catalyses transhydrogenation between analogues of NAD(H) and NADP(H). The characteristics of this reaction resemble those of the reaction catalysed by a complex of the NAD(H)- and NADP(H)-binding subunits of proton-translocating transhydrogenases from bacteria and mammals. It is concluded that the complete En. histolytica protein, which, along with similar proteins from other protozoan parasites, has an unusual subunit organisation, is also a proton-translocating transhydrogenase. The function of the transhydrogenase, thought to be located in organelles which do not have the enzymes of oxidative phosphorylation, is not clear.

[学科分类] 生物化学/生物物理

[关键词] Transhydrogenase;Proton pump;Nucleotide binding;Hydride transfer;Protozoan parasite;Entamoeba histolytica;dI;the NAD(H)-binding component of transhydrogenase;dIII;the NADP(H)-binding component;ehdIII–dI;the tethered complex of dIII and dI of the putative transhydrogenase from Entamoeba histolytica;AcPdAD+;acetyl pyridine nicotinamide dinucleotide (oxidised form)