. "\"The chemical reactions and pathways resulting in the breakdown of any member of a large group of derivatives or analogs of porphyrin. Porphyrin consists of a ring of four pyrrole nuclei linked each to the next at their alpha positions through a methine group.\" [GOC:jl, ISBN:0198506732]" . . "porphyrin-containing compound catabolic process" . . . . "porphyrin breakdown" . "porphyrin catabolic process" . "porphyrin catabolism" . "porphyrin degradation" .