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The G6P is then converted to 6-phosphogluconolactone in the presence of enzyme glucose-6-phosphate dehydrogenase (an oxido-reductase) with the presence of co-enzyme nicotinamide adenine dinucleotide phosphate (NADP +). which will be reduced to nicotinamide adenine dinucleotide phosphate hydrogen along with a free hydrogen atom H +.
A covalent intermediate characteristic of a ping pong mechanism is formed between the enzyme and the sugar via the phosphate group. Polyprenol phosphate (Pren-P), a membrane substrate, attacks the covalent intermediate, or phosphoglycosyl adduct, resulting in turnover of enzyme and attachment of the sugar to the Pren-P acceptor within the membrane.
The phosphoryl group on PEP is eventually transferred to the imported sugar via several proteins. The phosphoryl group is transferred to the Enzyme E I (EI), Histidine Protein (HPr, Heat-stable Protein) and Enzyme E II (EII) to a conserved histidine residue, whereas in the Enzyme E II B (EIIB) the phosphoryl group is usually transferred to a cysteine residue and rarely to a histidine.
This step is the enzymatic transfer of a phosphate group from 1,3-bisphosphoglycerate to ADP by phosphoglycerate kinase, forming ATP and 3-phosphoglycerate. At this step, glycolysis has reached the break-even point: 2 molecules of ATP were consumed, and 2 new molecules have now been synthesized.
The dimers can dimerize as well to form a homotetrameric enzyme. A double phosphoryl transfer mechanism was proposed on the basis of this study: this would involve breakage of PEP's phosphorus-oxygen bond to form a phosphoenzyme intermediate, followed by transfer of the phosphoryl group from the enzyme to carbon-3, forming PPR.
Hence, this enzyme has one substrate, β-D-glucose 1-phosphate, and one product, β-D-glucose 6-phosphate. This enzyme belongs to the family of isomerases, specifically the phosphotransferases (phosphomutases), which transfer phosphate groups within a molecule. The systematic name of this enzyme class is beta-D-glucose 1,6-phosphomutase.
Transphosphorylation is a chemical reaction in which a phosphate group or a phosphono group is transferred between a substrate and a receptor. [1] There are various phosphate esters in living body including nucleic acid, and phosphorylation reaction related to their synthesis and interconversion is the basis of biochemical reaction.
Phosphoglycerate kinase (EC 2.7.2.3) (PGK 1) is an enzyme that catalyzes the reversible transfer of a phosphate group from 1,3-bisphosphoglycerate (1,3-BPG) to ADP producing 3-phosphoglycerate (3-PG) and ATP : 1,3-bisphosphoglycerate + ADP ⇌ glycerate 3-phosphate + ATP. Like all kinases it is a transferase.