MARKED ENHANCEMENT IN THE REDUCTIVE DEHALOGENATION OF HEXACHLOROETHANE BY A THR319ALA MUTATION OF CYTOCHROME-P450 1A2

Mutation of the conserved Thr319 residue to Ala of cytochrome P4501A2 (CYP1A2) increased the value of V-max Q-fold for reductive dehalogenat ion of hexachloroethane in the reconstituted system under anaerobic co nditions. The Thr319Ala mutation also increased the elimination over s ubstitution product ratio by 5-fold. The addition of aliphatic alcohol s increased by 22-fold the activity obtained with the wild type and va ried the elimination over substitution product ratio. Increasing pH in creased the ratio of elimination over substitution by primarily affect ing the rate of elimination. (C) 1998 Academic Press.