[A model of the allosteric behavior of phosphofructokinase from rabbit muscles determined by the action of adenine nucleotides].
A complex of programs in BASIC has been elaborated, the first part of which is intended for the calculation of concentrations of different ionic forms of the metabolites that are engaged in a complex equilibrium system of the metal-ligand mixture-H+ type. The second part of the complex is employed in the simulation of allosteric kinetics on the basis of the Monod-Wyman-Changeux model. The calculation of ratios of different components in the Mg2+-AMP, ADP and ATP system is used for the semi-quantitative description of regulation of rabbit muscle phosphofructokinase by adenyl nucleotides at pH 7.0, 7.5 and 8.0. The use of computer optimization by the net method over the four experimental curves jointly makes it possible to determine self-concerted parameters of the model, which, in its turn, permits to give a "unified" description of the whole body of experimental evidence (48 curves). Fourteen variants of the model differing in the number of pH-dependent parameters and ATP ionic forms have been compared. The statistical significance of the differences between the variants has been analyzed. The "optimal" and "minimal" models have been elicited providing the most exact and most "unified" description of the experimental data, respectively. The allosteric effect of free ATP and its Mg2+-complex has been demonstrated. It follows from the computations that free ATP should activate phosphofructokinase with a very high affinity for the enzyme, while Mg-ATP2- should inhibit the enzyme (at the regulatory site).
Cherepanov
D A
DA
Rapanovich
I I
II
D000227:Adenine Nucleotides / Q000378:metabolism*; D000494:Allosteric Regulation; D000818:Animals; D066298:In Vitro Techniques; D007700:Kinetics; D008954:Models, Biological; D009132:Muscles / Q000201:enzymology*; D010732:Phosphofructokinase-1 / Q000378:metabolism*; D011817:Rabbits
D000227:Adenine Nucleotides; D010732:Phosphofructokinase-1
Modelirovanie allostericheskogo povedeniia fosfofruktokinazy iz myshts krolika, opredeliaemogo deĭstviem adenilovykh nukleotidov.