A route has been devised for synthesis of both enantiomers of the spiro-lactam. The enzyme uroporphyrinogen III synthase (cosynthetase), which converts hydroxymethylbilane into uroporphyrinogen III, is competitively inhibited more than twenty times more strongly by one enantiomer of than by the other. This finding adds further strong support to the view that cosynthetase acts by generating the spiro-pyrrolenine as an intermediate.
Department of Chemistry
University of Cambridge