both were anionic at ph 8.3 , did not require metal ions , and were not sensitive to iodine , but were inhibited by cu ( 2+ ) and readily inactivated by heat . p-chloromercuribenzoate , iodoacetate , p-aminobenzoate , and substrates and inhibitors of dd-carboxypeptidase had no effect on beta-lactamase activity .
C0003075
anionic
C0022023
ions