5-Aminolevulinic-acid synthetases from Rhodopseudomonas spheroides Y. Comparison of the purification and properties of enzymes extracted from bacteria grown in different iron concentrations.

The two 5-aminolevulinic acid synthetases of Rhodopseudomonas spheroides Y. were extracted from cells grown in a 'low-iron' medium and purified. They have a specific activity 10-fold higher than the 'high-iron' enzymes described by us previously and have the same properties except that they do not contain any iron and have one free-SH group more per mole of enzyme (2 for E1; , for E2) Their inhibition by adenosine triphosphate and iron and their oxidation-reduction sensitivity are discussed in terms of light, oxygen and heme feed-back regulation of bacteriochlorophyll sunthesis.