DETOXIFICATION OF L-CANAVANINE BY THE TOBACCO BUDWORM, HELIOTHIS-VIRESCENS [NOCTUIDAE]

The detoxification of L-canavanine and the ability of this natural product to induce a protein able to detoxify it were investigated in the tobacco budworm, Heliothis virescens. The available evidence indicates that this detoxification mechanism is part of larval constitutive metabolism and not induced in response to canavanine. H. virescens larvae, administered 5 mg/g L-canavanine supplemented with 37.7 kBq L-[guanidinooxy-14C]canavanine, were sacrificied 0, 1, 2, 4, 6, and 12 h postinjection. The principal products of L-canavanine degradation were [14C]guanidine and [14C]urea. Homoserine formation was confirmed by automated amino acid analysis. This study demonstrates that the principal detoxifica tion pathway for L-canavanine in H. virescens larvae is by reductive cleavage to guanidine and L-ho-moserine. © 1990, American Chemical Society. All rights reserved.