Noun
penam (plural penams)
(organic chemistry) A bicyclic ring system containing a beta-lactam moiety fused with a five-member thiazolidine ring; the common core skeleton of the penicillin subclass of beta-lactam antibiotics.
ACV is oxidatively cyclized (two cyclizations by a single enzyme) to bicyclic intermediate isopenicillin N by isopenicillin N synthase (IPNS) to form the penam core structure. citation Various transamidations lead to the different natural penicillins. Source: Internet
The image shows that the thiazolidine ring and fused four-membered β-lactam are not in the same plane The term " penam " is used to describe the common core skeleton of a member of the penicillins. Source: Internet
The penam core has a molecular weight of 243 g/mol, with larger penicillins having molecular weights near 450—for example, cloxacillin has a molecular weight of 436 g/mol. Source: Internet