IRON ENZYMES IN IRON DEFICIENCY. VI. ACONITASE ACTIVITY AND CITRATE METABOLISM

Abstract

The enzyme aconitase loses most of its activity when incubated in dilute solution at 37[degree] C. The addition of .003 [image] ascorbic acid and Fe SO4 results in rapid reactivation of the enzyme. The aconitase activity of hearts, livers, and brains of Fe-deficient rats is normal but a consistent decrease in aconitase activity of kidneys from Fe-deficient rats is demonstrated. Aconitase from kidneys of Fe-deficient rats cannot be reactivated by adding Fe and ascorbic acid nor by adding extracts of normal kidney. Anemia produced by phenylhydrazine treatment or by bleeding when Fe supplements are given does not result in a decrease of rat kidney aconitase activity. The aconitase activity of Fe-deficient human leucocytes is normal. Plasma levels and urinary excretion of citrate after loading with citrate does not differ in iron-deficient and normal subjects.