. "The chemical reactions and pathways resulting in the formation 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." . . . . "porphyrin biosynthesis" . "porphyrin-containing compound biosynthetic process" . "porphyrin anabolism" . "porphyrin biosynthetic process" . "porphyrin formation" . "porphyrin synthesis" . . . . . . . .