The effect of γ-radiation on the NADP-malic enzyme from mango fruit, Mangifera indica - II. Kinetic and regulatory properties

1. 1. Malic enzyme purified from the fruit tissue of Mangifera indica was irradiated in aqueous solution and the effect of γ-irradiation on the catalytic and regulatory properties of the enzyme was investigated. 2. 2. Significant differences in some of the allosteric properties of the enzyme were found as reflected in the various Hill-coefficients. 3. 3. Changes in both the kinetic parameters V_max and K_m were observed; suggesting that irradiation leads not only to destruction of the active sites but also to a general denaturation of the enzyme. 4. 4. The physiological significance of the radiation induced alterations are discussed against the background of ripening and sensescence.