hydrolysis of antibiotic conferring resistance hydrolysis of beta-lactam antibiotic by metallo-beta-lactamase Mechanism of enzymatic degradation common to Ambler Class B beta-lactamases. One or two zinc atoms are used to orient a hydroxide nucleophile for attack of the beta-lactam ring. In contrast to serine beta-lactamases, no acyl-enzyme intermediate is formed. antibiotic_resistance ARO:3000203