Kinetics of the interactions of the chicken erythrocyte AMP deaminase with anthraquinone compounds.

Alizarine sulfonate, the anthraquinone containing both sulfonate and hydroxyl groups, showed an activating and inhibitory effect on the chicken erythrocyte AMP deaminase (EC 3.5.4.6). The cooperative effect of AMP, analyzed in terms of Hill coefficient, was decreased from 2.4 to 1.1 with the increase in the dye concentration, suggesting the dye as an allosteric activator of the enzyme. However, alizarine sulfonate acted as a mixed type inhibitor in the presence of higher level of AMP. The action of alizarine sulfonate can be accounted for by assuming that the dye binds to the enzyme at the allosteric-activating sites with a broad specificity toward nucleotide binding, and further at the specific inhibitory sites.