Control of Flux in the Glycolytic Pathway Essay Example | Topics and Well Written Essays - 500 words

Control of Flux in the Glycolytic Pathway - Essay Example In glycolysis, all the reactions that are catalyzed by phosphofructokinase, hexokinase, and pyruvate kinase are considered being virtually irreversible. These enyzymes would easily be expected to have both the regulatory, and the catalyzing roles. The enzymes will serve as a controlling site. All their functions are controlled by some reversible allosteric effectors binding or through the covalent modification. More so, the quantities of these vital enzymes are variable by the control of the transcription of meeting the shifting and altering metabolic needs. The amount of time that would be needed for the control of the reversible allosteric and the regulation by transcriptional and phosphorylation, is considered to be in seconds, milliseconds, and hours. In the mammalian glycolytic pathway, for example, phosphofructokinase is one of the most vital elements of control. Increased ATP levels allosterically inhibit the enzymes within the liver, thus reducing affinity for the fructose 6- phosphate. When the concentration of ATP is high, the hyperbolic curve binding of the fructose 6-phosphate will be converted to the signoidal one. This effect is elicited by ATP though the binding towards a specific regulatory site that would be distinct from the catalyzing site. The inhibition role of ATP, is reversed by AMP implying that the rate of activity for the enzyme will increase after the ratio of ATP/AMP is lowered. In this case, glycolisis will be stimulated once the charges of the energy are reduced. A reduction in the pH value will also stop the activity of phosphofructokinase. Once Phosphofructosekinase is inhibited by the hydrogen ions, excess formation of lactic acid will be prevented leading to a precipitous drop in the pH of blood. Thi s process is referred to as acidosis. In this case, some of the ATP will be salvaged from the initial ADP.