title: Opposite effects of cofilin and profilin from porcine brain on rate of exchange of actin-bound adenosine 5'-triphosphate.
abstract: Cofilin, an actin-binding protein isolated from porcine brain that reacts with actin in a 1:1 molar ratio [Nishida, E., Maekawa, S., & Sakai, H. (1984) Biochemistry 23, 5307-5313], decreases the rate of exchange of ATP bound to G-actin with 1,N6-ethenoadenosine 5'-triphosphate in solution. From analyses of the dependence of the exchange rate on the cofilin concentration under different KCl concentrations, dissociation constants (KD) for the cofilin-actin binding at 0, 50, and 140 mM KCl were determined to be 0.12, 0.15, and 0.25 microM, respectively. In contrast to cofilin, profilin isolated from porcine brain increases the rate of exchange of G-actin-bound ATP, like Acanthamoeba profilin. The kinetic analyses gave KD values for the profilin-actin binding of 1.1 and 1.5 microM, respectively, at 50 and 200 mM KCl.
mesh_terms: D051339:Actin Depolymerizing Factors; D000199:Actins / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000378:metabolism*; D003285:Contractile Proteins / Q000378:metabolism*; D007700:Kinetics; D008840:Microfilament Proteins; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D011189:Potassium Chloride / Q000494:pharmacology; D051304:Profilins; D011485:Protein Binding; D011506:Proteins / Q000378:metabolism*; D013552:Swine; D013816:Thermodynamics
chemical_list: D051339:Actin Depolymerizing Factors; D000199:Actins; D003285:Contractile Proteins; D008840:Microfilament Proteins; D009419:Nerve Tissue Proteins; D051304:Profilins; D011506:Proteins; D011189:Potassium Chloride; D000255:Adenosine Triphosphate