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Glycolysis is the metabolic pathway that converts glucose (C 6 H 12 O 6) into pyruvate and, in most organisms, occurs in the liquid part of cells (the cytosol). The free energy released in this process is used to form the high-energy molecules adenosine triphosphate (ATP) and reduced nicotinamide adenine dinucleotide (NADH). [ 1 ]
Aerobic glycolysis Glycolysis – The first stage is known as glycolysis, which produces 2 ATP molecules, 2 reduced molecules of nicotinamide adenine dinucleotide and 2 pyruvate molecules that move on to the next stage – the Krebs cycle. Glycolysis takes place in the cytoplasm of normal body cells, or the sarcoplasm of muscle cells.
"The metabolic pathway of glycolysis converts glucose to pyruvate via a series of intermediate metabolites. Each chemical modification (red box) is performed by a different enzyme. Steps 1 and 3 consume ATP (blue) and steps 7 and 10 produce ATP (yellow). Since steps 6-10 occur twice per glucose molecule, this leads to a net production of energy."
Hexokinase-I (HK-I) is an enzyme activator because it draws glucose into the glycolysis pathway. Its function is to phosphorylate glucose releasing glucose-6-phosphate (G6P) as the product. HK-I not only signals the activation of glucose into glycolysis but also maintains a low glucose concentration to facilitate glucose diffusion into the cell.
An alternative to glycolysis is the Pentose phosphate pathway (PPP): Depending on cellular conditions the PPP can produce NADPH (another energy transport form in the cell) or synthesize riboses (important for substances based on ribose like e.g. RNA) - the PPP is for example important in red blood cells.
In the glycolytic pathway, 1,3-BPG is the phosphate donor and has a high phosphoryl-transfer potential. The PGK-catalyzed transfer of the phosphate group from 1,3-BPG to ADP to yield ATP can power [clarification needed] the carbon-oxidation reaction of the previous glycolytic step (converting glyceraldehyde 3-phosphate to 3-phosphoglycerate).
The enzyme-catalysed transfer of a phosphoryl group from ATP is an important reaction in a wide variety of biological processes. [1] Phosphofructokinase catalyses the phosphorylation of fructose-6-phosphate to fructose-1,6-bisphosphate, a key regulatory step in the glycolytic pathway.
Fru-2,6-P 2 contributes to the rate-determining step of glycolysis as it activates enzyme phosphofructokinase 1 in the glycolysis pathway, and inhibits fructose-1,6-bisphosphatase 1 in gluconeogenesis. [1] Since Fru-2,6-P 2 differentially regulates glycolysis and gluconeogenesis, it can act as a key signal to switch between the opposing ...