Control of Flux in the Glycolytic Pathway - Essay Example

Control of Flux in the Glycolytic PathwayThe flux in the glycolytic pathway needs to adjust following the conditions outside and inside the cell. The rate at which glucose is converted to pyruvate is controlled to satisfy the two major cellular needs. The first need involves the production of ATP that is produced through the glucose degradation. The second need involves the provision of the synthesis reaction building blocks like the fatty acids formation. In the pathway metabolism, the enzymes responsible for the calysation of the basic irreversible reactions are considered being potential control sites.

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.

This process is referred to as acidosis. At the time when ATP is used fast, the adenylate kinase enzyme could form ATP from ADP using the reactionADP+ADP ATP+AMP.In this case, some of the ATP will be salvaged from the initial ADP. In addition, AMP will change into being the signal for the lower state of energy. In addition, using AMP as an allosteric regulator offers a sensitive control. This means that the total pool of adenylate (ATP, ADP, AMP) inside the cell will be constant for a short period of time.

The ATP concentration will be greater than that of ADP. On the other hand, the concentration of ADP will, in turn be greater than that of AMP. In most cases, the small changes in the percentage of ATP will lead to huge percentages in the other adenylate nucleotides percentages. The magnification of small ATP changes to large changes results into tight control through increasing the sensitivity range of the phosphofructokinase.