Effect of Peroxisomicine and Related Anthracenones on Catalase Activity

Abstract

Dimeric anthracenones were isolated from toxic plants of the genus Karwinskia (Rhamnaceae). T 514 or peroxisomicine A₁ is one of these toxic compounds which produces an irreversible and selective damage on the peroxisomes of yeast cells in vivo. In this paper we now report the inhibitory effect in vitro of peroxisomicine A₁ and other structurally related anthracenones on liver catalase activity. The peroxisomicine A₁ produces a non-competitive inhibition with respect to H₂O₂ on bovine, dog, and mouse liver catalases. In the three cases V_max was decreased whereas K_m was unaffected. Other dimeric anthracenones of natural origin were also found to be inhibitors of bovine liver catalase. There is a relationship between structure and degree of inhibition of all anthracenonic compounds tested. Peroxisomicine A1 and peroxisomicine A2 caused the highest degree of inhibition (IC₅₀ = 3.34 and 3.64 µM, respectively).

Key words

Karwinskia - peroxisomicine - Rhamnaceae - anthracenones - catalase - inhibition