The antimalarial drug, chloroquine, interacts with lactate dehydrogenase from Plasmodium falciparum

Abstract

We have previously shown that a radioiodinated photoreactive analogue of chloroquine, [125I]N-(4-(4-diethylamino-1-methylbutylamino)quinolin-6- y1)-4-azido-2-hydroxybenzamide ([125I]ASA-Q), specifically labels two proteins in Plasmodium falciparum with apparent molecular weights (M(r)) of 42 and 33 kDa (Foley M, Deady LW, Ng K, Cowman AF, Tilley L. J Biol Chem 1994;269:6955-6961). We now report the identification of the 33 kDa protein. The 33 kDa protein was purified from Plasmodium falciparum using photoaffinity labeling with [125I]ASA-Q to monitor the enrichment process. N-terminal sequence analysis of the purified protein revealed exact identity of the first 35 amino acids with P. falcipa..