ALUMINUM INHIBITION OF HEXOKINASE-ACTIVITY IN-VITRO - A STUDY IN BIOLOGICAL AVAILABILITY

We have used the HK/G6PDH coupled enzyme assay to determine the biolog ical availability of aluminum in mixed-ligand media of biological inte rest. The biological availability of aluminum was measured as the inhi bition of the activity rate of the assay and was shown to be dependent upon the equilibration state of the aluminum stock solutions (prior t o their addition to the assay) and the comparative reaction kinetics o f competitive aluminum equilibria in the assays. Aluminum was found to inhibit the assay, however, the inhibition by aluminum was abolished when silicic acid was present in both the aluminum stock solution and the assay medium. The assay is proposed as a model system for investig ating the biological availability of aluminum in heterogenous media of biochemical significance.