Catalyzes the last step of heme biosynthesis by inserting ferrous iron into protoporphyrin IX to produce protoheme. Produces heme for photosynthetic cytochromes, and for proteins involved in abiotic and biotic stress responses (PubMed:24329537). May play a role in the quality control of individual chloroplasts during photo-oxidative stress through regulation of heme biosynthesis (PubMed:26494759). 2 H(+) + heme b = Fe(2+) + protoporphyrin IX Porphyrin-containing compound metabolism; protoheme biosynthesis; protoheme from protoporphyrin-IX: step 1/1. (PubMed:11602264) shows experimental evidences that FC2 is not present in Arabidopsis mitochondria in vivo. A number of isoforms are produced. According to EST sequences. Expressed in leaves and flowers. Down-regulated by wounding or oxidative stress. Abnormal, small, and pale green rosette leaves (PubMed:24329537, PubMed:26494759). Low contents in chlorophylls, carotenoids and photosynthetic proteins in leaves. Impaired photosynthetic performance. Increased resistance to salt and flagellin treatment (PubMed:24329537). Increased sensitivity to de-etiolation (PubMed:26494759). Belongs to the ferrochelatase family.