V Pentostam, an uncharacterized complex of Sb and carbohydrate derived from gluconic acid, is concentrated by Leishmania amastigotes via protein binding. Biochemical consequences of the interaction of amastigotes with Pentostam are inhibition of parasite bioenergetics and inhibition of ATP synthesis. REFERENCES 1. J.C. Mottram and G.H. Coombs. Enzyme activities of amastigotes and promastigotes and their inhibition by antimonials and arsenicqls. Exper. Parasitol. 59:151 (1985). 125 2. S.L. Croft, K.D. Neame and C.A. Homewood. Accumulation of Sb] sodium stibogluconate by Leishmania mexicana amazonensis and Leishmania donovani in vitro. Compo Biochem. Physiol. 68c:95 (1981). 3. J.D. Berman, J.V. Gallalee, and B.D. Hansen. Leishmania mexicana: uptake of sodium stibogluconate (Pentostam) and pentamidine by parasite and macrophages. Exper. Parasitol. 64:127 (1987). 4. J.D. Berman, D. Waddell and B.D. Hanson. Biochemical meChanisms of the antileishmanial activity of sodium stibogluconate. Antimicrobial Agents Chemotherapy. 27:916 (1985). 5. J.D. Berman, J.V. Gallalee, and J.M. Best.Sodium stibogluconate (Pentostam) inhibition of glucose catabolism via the glycolytic pathway, and fatty acid B-oxidation in Leishmania mexicana amastigotes. Biochem. Pharmacol. 36:197 (1987). 6. D.T. Hart and G.H. Coombs. Leishmania mexicana: Energy metabolism of amastigotes and promastigotes. Exper. Parasitol. 54:397 (1982). 478 EFFECTS OF SINEFUNGIN ON CELLULAR AND BIOCHEMICAL EVENTS IN PROMASTIGOTES OF LEISHMANIA d. donovani Fran oise Lawrence, and MaIka Robert-Cero Institut de Chimie des Substances Naturelles C.N.R.S.