Studies on the induction of aryl hydrocarbon(benzo[a]pyrene) hydroxylase in Neurospora crassa, and its suppression by sodium selenite

Abstract

1. Six fungal species were grown in the presence of benzo[a]pyrene (BP); four showed benzo[a]pyrene hydroxylase (aryl hydrocarbon hydroxylase, AHH) activity. Penicillium sp. and Neurospora crassa metabolized BP to a limited extent.

2. N. crassa AHH activity was induced by BP, the major product of metabolism being 3-hydroxy-BP. Both induction of AHH activity and metabolism of BP were suppressed by sodium selenite in the growth medium.

3. Two polypeptides, unique to BP-grown cells, were revealed by two-dimensional electrophoretic separation of [³⁵S]methionine-labelled proteins in N. crassa cell extracts.

4. In selenium-grown cells the synthesis of BP-specific polypeptides was severely inhibited.