Radiation inactivation of multimeric enzymes: application to subunit interactions of adenylate cyclase.

摘要: Radiation inactivation has been applied extensively to determine the molecular weight of soluble enzyme and receptor systems from slope a linear ln (activity) vs. dose curve. Complex nonlinear curves are predicted for multimeric systems, composed distinct subunits in equilibrium with complexes. For system A1 + A2----A1A2, an active A1A2 complex (associative model), curve is high dissociation constant, K. If monomer, A1, all activity (dissociative activation hump at low radiation if inactive subunit, A2, higher than upward concavity when A2 smaller A1. In general, model multistep mechanism fulfills characteristics associative or dissociative reaction step forming reaction. Target theory gives subunit limiting dose. energy transfer occurs among multimer, single component concave two more components. The use as method size assembly discussed specific application hormone-sensitive adenylate cyclase system. It shown that presented accompanying paper can be used select best out series seven proposed mechanisms by hormone.