title: Energy utilization for control.
abstract: When, on addition of a suitable substrate, a chemical potential is applied to an enzymic process such as glycolysis or respiration, whether in solution or membrane-bound, all components of the process pass into a nonequilibrium state, which might be steady or non-steady and which produces the following phenomena: (1) The reactants of each enzymic reaction are displaced from their equilibrium concentration, and energy is dissipated; (2) Part of each enzyme is transferred to a transition state of its catalytic function as well as isosteric and allosteric controlling functions, displaying local and gross conformation changes, and a rate-controlling state is generated; (3) In cyclic portions of a process futile events and chemical interconversion may occur; (4) In self- and cross-coupled portions of a process, oscillation with periodic changes of states and spatial propagation as well as instabilities may be observed; (5) At each step of a process, depending on the rate of flux and the specific enzymic function, a varying proportion of the free energy changes--which are concentration-dependent and derived from the overall potential of the system-is contributed to the control of flux rates. This will be exemplified for enzymes of bioenergetic pathways.
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000262:Adenylyl Cyclases / Q000378:metabolism; D000494:Allosteric Regulation; D002384:Catalysis; D002462:Cell Membrane / Q000201:enzymology; D003201:Computers; D003580:Cytochromes / Q000378:metabolism; D004579:Electron Transport; D004734:Energy Metabolism; D005636:Fructosephosphates / Q000378:metabolism; D005956:Glucose-6-Phosphate Isomerase / Q000378:metabolism; D005958:Glucosephosphates / Q000378:metabolism; D006019:Glycolysis; D007700:Kinetics; D008954:Models, Biological; D009243:NAD / Q000378:metabolism; D010732:Phosphofructokinase-1 / Q000378:metabolism; D011770:Pyruvate Kinase / Q000378:metabolism; D012440:Saccharomyces / Q000378:metabolism; D013057:Spectrum Analysis; D013816:Thermodynamics
chemical_list: D003580:Cytochromes; D005636:Fructosephosphates; D005958:Glucosephosphates; D009243:NAD; D000255:Adenosine Triphosphate; D010732:Phosphofructokinase-1; D011770:Pyruvate Kinase; D000262:Adenylyl Cyclases; D005956:Glucose-6-Phosphate Isomerase