Studies on the cell-free biosynthesis of β-lactam antibiotics

Abstract

Cell walls of Cephalosporium acremonium mycelia were lysed by enzyme preparations from either Helix pomatia (snail) digestive juice or Cytophaga. The yield of protoplasts depended on the lytic-enzyme preparation and the age of the culture, and it increased after the mycelia were pretreated with dithiothreitol. A cell-free preparation, obtained by osmotic lysis of protoplasts, synthesized labelled penicillin N from L-[14C]valine. Approx. 0.03-0.06% of the amino acid was incorporated into penicillin N. Under conditions of penicillin N synthesis, the broken-protoplast preparation failed to produce significant amounts of cephalosporin C or its precursors, deacetylcephalosporin C and deacetoxycephalosporin C.