Haemoglobin synthesis stas with?

Glycine REF: Harper 26th e p. 271-275 Steps of porphyrin ring synthesis: Enzyme I Location Substrate Product porphyria ALA synthase Mitochondrion Glycine, succinyl CoA D-Aminolevulinic acid none ALA dehydratase Cytosol D-Aminolevulinic acid Porphobilinogen ALA? Dehydratase deficiency PBG deaminase Cytosol Porphobilinogen Hydroxymethyl bilane Acute intermittent porphyria Uroporphyrinogen Cytosol III synthase Hydroxymethyl bilane Uroporphyrinogen III Congenital erythropoietic porphyria Uroporphyrinogen Cytosol III decarboxylase Uroporphyrinogen III Coproporphyrinogen III Porphyria cutanea tarda Coproporphyrinogen III oxidase Mitochondrion Coproporphyrinogen III Protoporphyrinogen IX Coproporphyria Protoporphyrinogen oxidase Mitochondrion Protoporphyrinogen IX Protoporphyrin IX Variegate porphyria Ferrochelatase Mitochondrion Protoporphyrin IX Heme Erythropoietic protoporphyria Heme synthesis--note that some reactions occur in the cytoplasm and some in the mitochondrion (yellow)