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. Author manuscript; available in PMC: 2014 Feb 14.
Published in final edited form as: Met Ions Life Sci. 2013;12:241–278. doi: 10.1007/978-94-007-5561-1_8

Figure 6.

Figure 6

Heme biosynthesis pathway in eukaryotes. (a) Glycine is transported into the mitochondrial matrix via an unknown mechanism where it is combined with succinyl-CoA by ALA synthase (ALAS) to form ALA. (b) ALA is transported out to the cytosol where it is converted to CPgenIII through four conserved steps. (c) ABCB6 is the transporter proposed to import CPgenIII to the IMS where it is converted first to PPgenIX by CPOX, then to protoporphyrin IX (PPIX) by PPOX. (d) PPIX is transported to the matrix where iron is inserted by ferrochelatase (FECH). The proposed Fe(II) importers are Mrs3/4 (Mfrn1/2 in mammalian cells). (e) Assembled heme is inserted into target apo proteins to form hemoproteins in the mitochondria, possibly aided by FECH. (f) Heme is inserted into target apo proteins in the cytosol, possibly aided by GSTs.