Search results
Results from the WOW.Com Content Network
[2] [3] "Phosphoryl" groups are covalently bonded by a single bond to an organic molecule, phosphate group(s) or another "phosphoryl" group(s), and those groups are sp 3 hybridized at the phosphorus atom. [4] The term "phosphoryl" in the mentioned branches is usually used in the description of catalytic mechanisms in living organisms.
Phosphorylation allows cells to accumulate sugars because the phosphate group prevents the molecules from diffusing back across their transporter. Phosphorylation of glucose is a key reaction in sugar metabolism. The chemical equation for the conversion of D-glucose to D-glucose-6-phosphate in the first step of glycolysis is given by:
At pH 1 or lower, the phosphoric acid is practically undissociated. Around pH 4.7 (mid-way between the first two pK a values) the dihydrogen phosphate ion, [H 2 PO 4] −, is practically the only species present. Around pH 9.8 (mid-way between the second and third pK a values) the monohydrogen phosphate ion, [HPO 4] 2−, is the only species ...
In the final step of glycolysis, pyruvate kinase transfers a phosphoryl group from phosphoenolpyruvate to ADP, generating ATP and pyruvate. Hexokinase is the most common enzyme that makes use of glucose when it first enters the cell. It converts D-glucose to glucose-6-phosphate by transferring the gamma phosphate of an ATP to the C6 position.
Since orthophosphoric acid has three −OH groups, it can esterify with one, two, or three alcohol molecules to form a mono-, di-, or triester. See the general structure image of an ortho- (or mono-) phosphate ester below on the left, where any of the R groups can be a hydrogen or an organic radical. Di- and tripoly- (or tri-) phosphate esters ...
It was found that an enzyme, named phosphorylase kinase and Mg-ATP were required to phosphorylate glycogen phosphorylase by assisting in the transfer of the γ-phosphoryl group of ATP to a serine residue on phosphorylase b. Protein phosphatase 1 is able to catalyze the dephosphorylation of phosphorylated enzymes by removing the phosphate group.
The pyrophosphate anion has the structure P 2 O 4− 7, and is an acid anhydride of phosphate. It is unstable in aqueous solution and hydrolyzes into inorganic phosphate: P 2 O 4− 7 + H 2 O → 2 HPO 2− 4. or in biologists' shorthand notation: PP i + H 2 O → 2 P i + 2 H +
Substrate-level phosphorylation exemplified with the conversion of ADP to ATP. Substrate-level phosphorylation is a metabolism reaction that results in the production of ATP or GTP supported by the energy released from another high-energy bond that leads to phosphorylation of ADP or GDP to ATP or GTP (note that the reaction catalyzed by creatine kinase is not considered as "substrate-level ...