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Purification and Properties of δ-Aminolevulinate Dehydratase from Tissues of Two Strains of Mice

1966; Elsevier BV; Volume: 241; Issue: 23 Linguagem: Inglês

10.1016/s0021-9258(18)96372-6

1083-351X

David Coleman,

Neonatal Health and Biochemistry

Abstract The activity of δ-aminolevulinate dehydratase in mouse tissues is under the genetic control of two alleles at the levulinate (Lv) locus. δ-Aminolevulinate dehydratase has been isolated and extensively purified from the livers and spleens of two strains of mice; the AKR/J strain, homozygous for the Lva allele which has high tissue δ-aminolevulinate dehydratase activity, and the C57BL/6J strain, homozygous for the Lvb allele which has low tissue δ-aminolevulinate dehydratase activity, only one-third of that seen in Lva homozygotes. δ-Aminolevulinate dehydratase isolated from liver and spleen of each genotype has identical physical, chemical, and enzymic properties, which strongly suggests that the levulinate locus acts by controlling the amount rather than the structure of δ-aminolevulinate dehydratase. The δ-aminolevulinate dehydratase activity in spleen, normally only one-fifth of that seen in liver, can be increased to the normal liver activity characteristic of each genotype by making the mice anemic with repeated injections of phenylhydrazine. Mouse δ-aminolevulinate dehydratase is similar in most respects to that isolated from other species. The enzyme requires sulfhydryl compounds for maximal activity, is relatively heat stable, has a pH optimum of 6.5, Km of 4 x 10-4 m, and an approximate molecular weight of 270,000. However, in contrast to δ-aminolevulinate dehydratase from other species, the mouse enzyme is activated by ethylenediaminetetraacetate, Hg2+, and Fe2+ ions.