Authors

P Jirawatcharadech¹; G Camarda¹; C Yunta-Yanes¹; M J Paine¹; G Biagini¹; S A Ward¹;  ¹ Liverpool School of Tropical Medicine

Discussion

NADPH-cytochrome P450 reductase is a membrane-bound protein required  for electron transfer from NADPH to cytochrome p450 (CYPs). In humans, CYPs are essential for biotransformation of potentially toxic compounds. A homologous of human CPR has been identified in Plasmodium falciparum, however; a sequence-conserved CYP has not been reported in the genome. The absence of a CYP in P. falciparum raises the question of what alternative role and function of the PfCPR. We report here the expression of a functional truncated PfCPR in Escherichia coli. The soluble protein was successfully purified by Ni-NTA affinity followed by SP sepharose chromatography. A spectral characterisation of purified PfCPR was recorded in both oxidised and reduced forms. Initial steady-state enzyme kinetics of cytochrome c reduction in PfCPR were performed. The inhibitory effects of adenosine analogs (e.g. NAD, NADH, NADP, and 2',5'-ADP) and the flavoprotein inhibitor (e.g. diphenyliodonium chloride) on PfCPR activity were studied and are described herein.