NON-IRON PORPHYRINS INHIBIT BETA-HEMATIN (MALARIA PIGMENT) POLYMERIZATION

Infrared spectroscopy was used to evaluate the effect of non-iron porp hyrins (protoporphyrin IX and haematoporphyrin) on haematin polymerisa tion to beta-haematin at acidic pH. Both molecules effectively inhibit ed the reaction, with haematoporphyrin 6 times as active as protoporph yrin IX, We postulated that the interaction between the pi electron sy stem of porphyrin rings leads to the formation of pi-pi adducts, which inhibit polymer elongation in the same way as antimalarial drugs (e.g ., chloroquine); the presence of hydroxyl groups able to bind haem iro n enhances activity. (C) 1997 Federation of European Biochemical Socie ties.