Table of Contents
Why does ATP have high phosphoryl transfer potential?
Answer: ATP has a high phosphoryl group transfer potential because B. cleavage of either of its two phosphoanhydride bonds proceeds with a large negative ΔG°’ of hydrolysis.
What does the phrase high phosphoryl transfer potential substrate mean?
Phosphoryl-transfer potential―the standard free energy of hydrolysis—is a means of comparing the tendency of organic molecules to transfer a phosphoryl group to an acceptor molecule. ATP has a higher phosphoryl- transfer potential than glycerol 3-phosphate.
What general factors contribute to the high phosphoryl group transfer of ATP?
The four general factors that contribute to ATP’s high phosphoryl-transfer potential are: 1) charge repulsion, 2) resonance stabilization, 3) increase in entropy, and 4) stabilization by hydration. Compare ATP to acetyl CoA. Acetyl CoA (CoA) is an activated high-energy carrier with two carbon acetyl groups.
What enzyme can catalyze the formation of the glycolytic intermediate with a high phosphoryl transfer potential from 3 Phosphoglycerate?
phosphoglycerate kinase
Reaction 7: phosphoglycerate kinase and the first ATP forming reaction. In the seventh step of the glycolytic pathway, phosphoglycerate kinase (EC 2.7.2.3) catalyzes the transfer of the high-energy phosphoryl group from the acyl phosphate of 1,3-BPG to ADP to form ATP and 3-phosphoglycerate (3-PG).
What is phosphoryl group transfer?
Phosphoryl transfer is the name given to the chemical process of the transfer of the phosphoryl group (PO3) from a phosphate ester or anhydride to a nucleophile. The opposite process, the formation of phosphate esters, is termed phosphorylation and is accomplished in biological systems by kinases.
What is meant by phosphate group transfer potential?
The group transfer potential is defined here as the sum of the atomic energies forming the group in ATP minus the sum of the energies of the same atoms in inorganic phosphate. This is accompanied by a concomitant change in the energy of reaction from -168.6 to -24.9 kcal/mol.
Is a phosphoryl group electrophilic?
During this reaction, a lone pair of electrons on an oxygen atom in a water molecule “attacks” the Phosphorus in the terminal phosphate group, removing the the phosphate group from the ATP molecule. During this reaction, the water molecule is the nucleophile and the phosphoryl group is the electrophile.
Why are phosphate esters kinetically stable?
1. Phosphate esters are thermodynamically unstable, yet they are kinetically stable. Phosphate esters are stable because the inherent negative charges resist hydrolysis.
Which enzyme catalyzes the reaction forming the first high phosphoryl transfer potential compound in the glycolytic pathway that is not ATP?
Glycolysis occurs within the cytoplasm of both prokaryotic and eukaryotic cells. b. During the first step of glycolysis, an ATP molecule is consumed in order to add a phosphate group to glucose. This is a reaction catalyzed by the enzyme hexokinase.
Why are the intermediates of glycolysis phosphorylated?
Because the plasma membrane generally lacks transporters for phosphorylated sugars, the phosphorylated glycolytic intermediates cannot leave the cell. High-energy phosphate compounds formed in glycolysis (1,3-bisphosphoglycerate and phosphoenolpyruvate) donate phosphoryl groups to ADP to form ATP.
What does a phosphoryl group do?
Phosphoryl group takes part in biologically important reaction called phosphoryl transfer. The group it transferred from a phosphate ester to a nucleophile. Phosphates (such as adenosine triphosphate – ATP) are also involved in the process.