Catalyzes the pyridoxal 5'-phosphate (PLP)-dependent condensation of succinyl-CoA and glycine to form aminolevulinic acid (ALA), with CoA and CO2 as by-products (By similarity). Contributes significantly to heme formation during erythropoiesis (By similarity).
Subcellular locations: Mitochondrion inner membrane
Localizes to the matrix side of the mitochondrion inner membrane.