protoporphyrin ( 3.3 or 6.6 microm ) ( and several other porphyrins ) and metallic ions ( 100 microm ) alone had little if any inhibitory effect , except for hg2+ which inhibited by 67 % at 10 microm and totally at 15 microm .
C0033733
protoporphyrin
C0032712
porphyrins