Porphyrins with four methyl, two ethyl, and two propionic acid side chains attached to the pyrrole rings. ... (12 Dec 1998) ... 
Type: Term Pronunciation: mez′ō-pōr′fi-rinz Definitions: 1. Porphyrin compounds resembling the protoporphyrins except that the vinyl side chains of the latter are reduced to ethyl side chains; mesobilane.