Beta lactam antibiotics Penicillin(over 50 compounds Share 4-sided ring(beta lactam ring) Natural penicillins Penicillin Mold Fungus Narrow range of action inactive against gram bacteria, no penetration of outer membrane Susceptible to penicillinase(beta lactamase) β- actam ring CH. S、/CH R-C-NH-CH+CH C Penicillinase R-C-NH-CH-HC C CH 11cH3 C-N CH- COOH O=C N—CH-cooH H OH Penicillin Penicilloic acid open theβ- actam ring of penicillins and cephalosporin 15Beta lactam antibiotics • Penicillin (over 50 compounds) – Share 4-sided ring (beta lactam ring) • Natural penicillins - Narrow range of action, inactive against Gram￾bacteria, no penetration of outer membrane - Susceptible to penicillinase (beta lactamase) open the β-lactam ring of penicillins and cephalosporin 15