δ-Aminolevulinic Acid Synthetase

Abstract

δ-Aminolevulinic acid synthesis has been demonstrated in both porphyric and normal liver homogenates. A study of the factors which affect δ-aminolevulinic acid production indicates that the enzyme δ-aminolevulinic acid synthetase can be measured in liver homogenates, with use of added glycine and endogenously generated succinyl coenzyme A. δ-Aminolevulinic acid production in this system is greater than in the isolated mitochondrial system previously used. The generation of succinyl coenzyme A from endogenous substrates is close to the optimal amount for δ-aminolevulinic acid production in liver homogenates. The determinations of hepatic δ-aminolevulinic acid production in a number of normal species agree well with estimates of the δ-aminolevulinic acid required for heme enzyme synthesis. The effects of factors influencing the synthesis of aminoacetone and δ-aminolevulinic acid in liver homogenates were compared and found to be markedly different.