Chemical details of porphyrin and heme synthesis

The various chemical intermediates are shown in black text with their structural formulae. The responsible enzymes that catalyze each step in the pathway are shown in blue. Enzyme inducers are shown in green and enzyme inhibitors are shown in red. Also shown in red are the diseases and associated symptoms resulting from partial function of 2 of these enzymes: acute intermittent porphyria resulting from partial function of the PBG-deaminase enzyme, and porphyria cutanea tarda resulting from partial function of the UPG III-decarboxylase enzyme. (Original figure by Clindberg, modified by Ross Boswell. Courtesy of Wikimedia Commons. Creative Commons Attribution-Share Alike 3.0 Unported license.)