title: Enzyme kinetic evidence of active-site involvement in the interaction between aldolase and muscle myofibrils.
abstract: The interaction of aldolase with the myofibrillar matrix of rabbit skeletal muscle has been investigated by means of its effect on kinetic parameters for the enzyme-catalyzed cleavage of fructose 1,6-bisphosphate. Involvement of the active site in the enzymic interaction with the thin filament of muscle is indicated, the association constant for competitive inhibition of catalysis (420,000 M-1) being in excellent agreement with the value of 410,000 M-1 obtained under the same conditions (pH 6.8, I 0.16) from partition equilibrium studies of the aldolase-myofibril interaction (Kuter, M.R., Masters, C.J. and Winzor, D.J. (1983) Arch. Biochem. Biophys. 225, 384-389). A second kinetic study, designed to take into greater account the inhibitory effects of substrate and other phosphate-containing metabolites on the interaction of enzyme with myofibrils, has substantiated further the concept of aldolase existing as an equilibrium mixture of cytoplasmic and filament-bound forms in muscle tissue.
mesh_terms: D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D005634:Fructose-Bisphosphate Aldolase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D005635:Fructosediphosphates / Q000378:metabolism; D007700:Kinetics; D009132:Muscles / Q000201:enzymology*; D009210:Myofibrils / Q000201:enzymology*; D011817:Rabbits; D013053:Spectrophotometry
chemical_list: D005635:Fructosediphosphates; D005634:Fructose-Bisphosphate Aldolase; C029063:fructose-1,6-diphosphate