Formation of the macrocyclic ring in tetrapyrrole biosynthesis.
D008025:Ligases / Q000378:metabolism; D008956:Models, Chemical; D011166:Porphyrins / Q000096:biosynthesis*; D011758:Pyrroles / Q000096:biosynthesis*; D013237:Stereoisomerism
D011166:Porphyrins; D011758:Pyrroles; D008025:Ligases