THE REGULATION OF THE VANADIUM CHLOROPEROXIDASE FROM CURVULARIA-INAEQUALIS

The effects of carbon and nitrogen source on the regulation of the van adium chloroperoxidase secreted by the fungus Curvularia inaequalis we re investigated. The addition of glucose showed a repressing effect on both the observed messenger RNA level and the measured enzyme activit ies, whereas the addition of glutamate as nitrogen source and the addi tion of both glutamate and glycerol had no effect. Addition of vanadat e had no effect on the level of mRNA. Eight hundred base pairs of the upstream promoter region of vCPO were sequenced and various features o f interest are highlighted. Closer inspection of the mycelium revealed that once secreted, vCPO probably remains tightly associated with the hyphae in two forms, one of which may be a preform of the enzyme. A p ossible cleavage event at the C-terminus may lower its potential for h yphal association and permit its disassociation into the growth medium . A putative role for the vanadium chloroperoxidase is put forward. (C ) 1997 Elsevier Science B.V.