Catalyzes the last step of heme biosynthesis by inserting ferrous iron into protoporphyrin IX to produce protoheme (PubMed:17416636, PubMed:24329537). Produces heme for photosynthetic cytochromes, but does not seem to be involved in stress responses (PubMed:24329537). May be involved in wound-induced supply of heme to defensive hemoproteins outside plastids (PubMed:17416636). Regulates the expression of photosynthesis-associated nuclear genes in undevelopped chloroplasts through production of heme (PubMed:21565502). 2 H(+) + heme b = Fe(2+) + protoporphyrin IX Porphyrin-containing compound metabolism; protoheme biosynthesis; protoheme from protoporphyrin-IX: step 1/1. (PubMed:9346891) describes experimental in vitro import of FC1 into mitochondria isolated from pea. However, (PubMed:11602264) shows experimental evidences that FC1 is not present in Arabidopsis mitochondria in vivo. Expressed in roots, leaves, stems and flowers (PubMed:12374307). Present in both leaves and roots (PubMed:17416636). Induced by sucrose, wounding, oxidative stress, salicylic acid, and during hypersensitive response to TMV infection (PubMed:12374307). Up-regulated by wounding and reactive oxygen species. Not regulated by methyl jasmonate. No visible phenotype, but decreased heme content in roots. Belongs to the ferrochelatase family.