B. PanijpanCh Mohan RaoD. BalasubramanianMahidol UniversityCentre for Cellular and Molecular Biology india2018-10-122018-10-121983-01-01Bioscience Reports. Vol.3, No.12 (1983), 1113-111715734935014484632-s2.0-0020973717https://repository.li.mahidol.ac.th/handle/20.500.14594/30450Hemin (ferriprotoporphyrin IX) is shown to form complexes with the chloroquine class of antimalarial drugs. The Soret band of hemin becomes optically active upon the addition of chiral drugs. Results on the hemin-induced quenching of the fluorescence of chloroquine are consistent with the formation of a 2:1 hemin:drug complex with a formation constant of 1.4×10⁷ at 298 K. Also a direct comparison of the drug-treated and drug-free parasites themselves, by the noninvasive photoacoustic spectroscopic method, reveals an in vivo interaction between endogenous hemin and the added drug. © 1983 The Biochemical Society.Mahidol UniversityBiochemistry, Genetics and Molecular BiologyArticleSCOPUS10.1007/BF01120204