The ratio of NADPH:NADP+ is normally about 100:1 in liver cytosol, making the cytosol a highly-reducing environment. (1) G6PD catalyzes the first oxidation reaction in the pentose phosphate shunt, in which glucose-6-phosphate is dehydrogenated to 6-phosphogluconolactone with the concurrent reduction of nicotinamide adenine dinucleotide phosphate (NADP). The pentose phosphate pathway is also called as the phosphogluconate pathway or hexose monophosphate shunt. Overview of Pentose phosphate pathway | HMP shunt. SIRT2-mediated deacetylation and activation of G6PD stimulates oxidative branch of PPP to supply cytosolic NADPH to counteract oxidative damage or support de novo lipogenesis. Pentose phosphate pathway is also called Hexose monophosphate pathway/ HMP shunt/ Phosphogluconate pathway. in Macrophages. The NADPH is required for biosynthetic reactions such as fatty acid synthesis, cholesterol synthesis, drug reduction, and as a cofactor for some non-synthetic enzymatic reactions. pentose phosphate pathway (PPP), pentose phosphate shunt, hexose monophosphate shunt or phosphogluronate pathway a PATHWAY for the metabolism of glucose. 16.18) can be summarised as follows: This pathway takes place in … The enzymes for HMP shunt are present in the cytosol of the cell. The reactions of this pathway are mostly enzyme-catalyzed in modern cells, however, they also occur non-enzymatically under conditions that replicate those of the Archean ocean, and are catalyzed by metal ions, particularly ferrous ions (Fe(II)). During this process, two molecules of NADP+are reduced to NADPH. • This is an alternative pathway to glycolysis and TCA cycle for the oxidation of glucose. To provide ribose 5 phosphate for nucleic acid biosynthesis Pentose phosphate pathway is an alternative route for the oxidation of glucose. Meaning of Pentose Phosphate Pathway (PPP): Major pathway for aerobic respiration of glucose is through glycolysis and Krebs cycle, however, an alternate pathway exists in many organisms. It is allosterically stimulated by NADP+ and strongly inhibited by NADPH. It reconnects with glycolysis because two of the end products of the pentose pathway are glyceraldehyde 3-p and fructose 6-p; two intermediates further down in the glycolytic pathway. , G6PD activity is also post-translationally regulated by cytoplasmic deacetylase SIRT2. Define pentose phosphate shunt. The Hexose Monophosphate Shunt is also known as “Pentose Phosphate Pathway” (PPP).This is an alternative Glucose oxidation pathway.The hexose monophosphate pathway is used for the production of NADPH from NADP.. It is more anabolic in nature. The pentose phosphate shunt has two phases, the oxidative phase (reactions 21 - 23), in which NADPH and pentose-5-phosphate are generated, and the non-oxidative phase (reactions 24 - 28), in which unused pentose-5-phosphate can be converted to other sugar intermediates and then returned to the glycolytic pathway as glyceraldehyde-3-phosphate and fructose-6-phosphate. While it involves oxidation of glucose, its primary role is anabolic rather than catabolic. In the oxidative phase, two molecules of NADP. It is an alternative route for the metabolism of glucose. The oxidative component of the pathway generates 2NADPH+2 H + in successive oxidation reactions starting with glucose-6-P and forming 6-P-gluconate (6PG), then ribulose-5-P (R5P)+CO 2. PPP is particularly important in animal cells where it functions as an alternative to GLYCOLYSIS and the KREBS CYCLE, although both mechanisms occur together.. Unless otherwise noted, LibreTexts content is licensed by CC BY-NC-SA 3.0. This pathway, which requires the presence of oxygen, is called pentose phosphate pathway (PPP) or hexose monophosphate shunt (HMS). • It is more anabolic in nature. Abstract. NADPH-utilizing pathways, such as fatty acid synthesis, generate NADP+, which stimulates glucose-6-phosphate dehydrogenase to produce more NADPH. Pentose phosphate pathway. In glucose-6-phosphate dehydrogenase deficiency, there is a defect in the first, irreversible step of the pathway.As a consequence NADPH production is decreased, making erythrocytes vulnerable to oxidative stress. Through the pentose phosphate shunt synonyms, pentose phosphate pathway the hexose monophosphate.. Biosynthesis reactions within cells ( erythrocytes ) of NADP of PPP to supply cytosolic NADPH to counteract oxidative damage support. Than catabolic converts glucose-6-phosphate to D-ribose-5-phosphate via 6-phosphogluconate the H2O2 would be converted ribulose-5-phosphate. 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