Two protein bands with strong esterase activity are present in broths of Nocavdia lactamdurans MA4213 cultures. One of them shows cephalosporin C acetylhydrolase (CAH) activity. This activity is maximal at 48 h of growth and shows a pattern of regulation slightly different from that of cephamycin production in medium supplemented with glucose (166 mM), glycerol (326 mM) or ammonium chloride (60 mM). The CAH activity was purified to homogeneity by DEAE-Sepharose ion-exchange, Sephadex G-75 gel filtration, and phenyl-Sepharose hydrophobic interaction chromatography. It showed a molecular mass of 72,100 Da. The N-terminus of the protein was determined and showed the amino acid sequence GGAAPGGPGAHPLWL-PAGKD. The enzyme showed K-m values of 7.0 mM and 8.3 mM for cephalosporin C and 7-aminocephalosporanic acid respectively but was not active on cephamycin C.