EFFECT OF PEROXISOMICINE AND RELATED ANTHRACENONES ON CATALASE ACTIVITY

Dimeric anthracenones were isolated from toxic plants of the genus Kar winskia (Rhamnaceae). T 514 or peroxisomicine A(1) is one of these tox ic compounds which produces an irreversible and selective damage on th e peroxisomes of yeast cells in vivo. In this paper we now report the inhibitory effect in vitro of peroxisomicine Al and other structurally related anthracenones on liver catalase activity. The peroxisomicine A(1) produces a non-competitive inhibition with respect to H2O2 on bov ine, dog, and mouse liver catalases. In the three cases V-max was decr eased whereas K-m was unaffected. Other dimeric anthracenones of natur al origin were also found to be inhibitors of bovine liver catalase. T here is a relationship between structure and degree of inhibition of a ll anthracenonic compounds tested. Peroxisomicine A(1) and peroxisomic ine A(2) caused the highest degree of inhibition (IC50 = 3.34 and 3.64 mu M, respectively).