cell-free supernatants from cells of streptomyces clavuligerus ( n.r.r.l . 3585 ) , which are actively synthesizing cephamycin c , transfer a carbamoyl group from carbamoylphosphate to a 3-hydroxymethylceph-3-em-4-carboxylic acid nucleus to form a 3-carbamoyloxymethylcephem .
C0007634
cells
C0007610
nucleus