| 摘要 |
<p>The present invention provides a biological system for expanding the dethiazolidine ring of penicillins into the dehydrothiazine ring of cephalosporins or cephalosporin precursors. In particular, the invention defines reaction conditions under which expandase enzyme can convert penicillin substrates other than penicillin N into cephalosporins. The invention therefore provides biological system for cephalosporin production from penicillins. In particular, the invention provides a system for producing DOAG and/or DAG, which can be enzymatically converted into 7-ADCA and 7-ADAC, which, in turn, can be enzymatically or chemically converted into valuable cephalosporins of commerce.</p> |
