What Is the Pentose Phosphate Pathway?
A method of oxidative breakdown of glucose by the pentose phosphate pathway. Since this pathway starts with glucose 6-phosphate (G-6-P), it is also known as hexose phosphate bypass. This pathway is performed in the cytoplasm and can be divided into two phases. The first stage begins with the dehydrogenation of G-6-P to 6-phosphate gluconolactone, and then hydrolyzes to 6-phosphate gluconic acid, which is then oxidatively decarboxylated to produce 5-phosphate ribulose. NADP + is an electron acceptor in all the above-mentioned oxidation reactions. In the second stage, ribulose 5-phosphate undergoes a series of transketone and transaldehyde reactions, and finally undergoes intermediate metabolites such as butyl phosphate, pentose phosphate and heptose phosphate to finally produce glyceraldehyde 3-phosphate and fructose 6-phosphate The latter two can re-enter the glycolytic pathway for metabolism.
Pentose phosphate pathway
- The main feature of the pentose pathway is the direct oxidative dehydrogenation and decarboxylation of glucose without having to go through
- The pentose phosphate pathway is the breakdown of a sugar that is commonly found in animals, plants and microorganisms
- 1. Incomplete oxidation pathway
- During the process, C6 is decomposed into C5 \ C4 \ C7
- 2. Complete oxidation
- Decomposed by C6 into 3 CO2 and C3 fragments
- 3, ribose 5-phosphate and the necessary raw materials for the synthesis of ribose, the decomposition of the body's core sugar is also this way
- 4.Erythritol 4-phosphate and sedum heptulose 7-phosphate are precursors for the synthesis of aromatic amino acids
- 5.Generating NADPH + H + can provide hydrogen required for bioanabolism
- 6. Link pentose metabolism to hexose metabolism
- 7. Regulated by two key enzymes, glucose-6-phosphate dehydrogenase and 6-phosphate gluconate dehydrogenase
- 1. Produce a large amount of NADPH, and provide reducing agents (forces) for various synthetic reactions of the cell, such as participating in the synthesis of fatty acids and sterols.
- 2. Guarantee the reduced state of glutathione in red blood cells. (Prevent membrane lipid peroxidation; maintain Fe2 + in heme;) (6-phosphate-glucose
- Dehydrogenase Deficiency-Anemia)
- 3. The intermediate products of this pathway provide raw materials for the synthesis of many substances, such as: 5-P-ribose, nucleotides, 4-P-erythrose, and aromatic amino acids
- 4. A series of intermediate products and enzymes in the non-oxidative rearrangement stage are the same as most intermediate products and enzymes in the Calvin cycle in photosynthesis, so the pentose phosphate pathway can be linked to photosynthesis and achieve some monosaccharide Mutual change.
- 5. The PPP pathway is a pathway that can be independently oxidized and decomposed by direct oxidation of glucose, and is also the main pathway for pentose metabolism. Therefore, it can complement and cooperate with EMP and TCA to increase the adaptability of the body.
- The pentose phosphate pathway refers to certain tissues of the body (such as liver, adipose tissue, etc.) starting from glucose 6-phosphate and catalyzed by glucose 6-phosphate dehydrogenase to form 6-phosphate gluconic acid and then metabolizing to pentose phosphate The process of metabolites, also known as hexose phosphate bypass.