Glycolysis is a metabolic pathway that uses glucose, a simple sugar, to produce free energy for the body. The free energy is used for high-energy molecules, such as adenosine triphosphate (ATP) and reduced nicotinamide adenine dinucleotide (NAD+). The glycolysis pathway involves a series of ten reactions that are catalyzed by enzymes.
Gluconeogenesis
Glycolysis is a process in which the body breaks down carbohydrates into glucose and releases energy as a byproduct. It consumes approximately six percent of the ATP synthesized during metabolism. Gluconeogenesis, in contrast, regenerates glucose from noncarbohydrate sources. Gluconeogenesis occurs in the liver and, to a lesser extent, in the kidney cortex.
Gluconeogenesis occurs in the cytosol and mitochondria. Several enzymes control it. Two of the main enzymes that drive glycolysis are shared in glycogenesis, but one is unique to gluconeogenesis. The first sub-step involves the addition of carbon dioxide to oxaloacetate to form pyruvate. The second sub-step involves the rearrangement of a double bond to produce glyceraldehyde.
The regulation of glycolysis occurs at multiple levels, including gene expression, allosteric regulation by small metabolites, and posttranslational modification. One recently discovered regulation is acetylation, which controls the activity of enzymes involved in glycolysis. The process is essential for maintaining the levels of glucose in the blood.
Phosphofructokinase
The PhosphofructokinasE (PFK) enzyme is involved in glycolysis, a metabolic process of carbohydrates. ATP, AMP, and ADP regulate it. ATP binds to the allosteric site of the T state, causing a shift in the equilibrium of the two states to favor the R state. This increase in the ratio of R to T state phosphofructokinase is a sigmoidal process, highlighting the enzyme’s cooperative nature.
The PFK enzyme is a rate-limiting enzyme in glycolysis. It catalyzes the phosphorylation of fructose-6-phosphate by ATP. It is present in red cells in both the M and L subunits. Mutations in PFK cause incomplete glycolysis. Fructose diphosphate (FDP) can relieve depression in PFK activity and increase the rate of glycolysis.
PFK has been implicated in the progression of diabetes mellitus. A deficiency of this enzyme reduces the heart’s metabolic flexibility and increases the risk of cardiomyopathy and other diseases associated with diabetes. PFK-2 is a crucial regulator of cardiac glycolysis and regulates substrate selection. However, the exact mechanism by which PFK-2 is regulated under normal conditions is unknown. This study has the potential to shed light on this critical metabolic process.
