Question

What do nucleotide kinases do? What do nucleoside diphosphate kinases do? This can also be done for what nucleotide by glycolysis or oxidative phosphorylation?

Answer 1

Nucleotide kinases are enzymes that transfer phosphate groups to facilitate ATP synthesis via substrate-level phosphorylation during glycolysis. Nucleoside diphosphate kinases exchange phosphate groups between nucleosides, important in maintaining cellular nucleotide balance. Glycolysis, which involves kinases like hexokinase, and oxidative phosphorylation are two distinct processes for ATP production.

Step-by-step explanation:

Nucleotide kinases are enzymes that facilitate the transfer of phosphate groups between different molecules. This process is typically involved in the substrate-level phosphorylation where, for instance, the enzyme phosphoglycerate kinase catalyzes the transfer of a high-energy phosphate from 1,3-bisphosphoglycerate to ADP, forming ATP during glycolysis. This is an energetically favorable reaction as the free energy released from hydrolyzing a phosphate from a high-energy compound like 1,3 diPG is used for ATP synthesis, and this particular reaction occurs twice per starting molecule of glucose, leading to a net synthesis of 2 ATP molecules in glycolysis.Nucleoside diphosphate kinases, on the other hand, are involved in maintaining the balance of different nucleotide triphosphates, such as ATP, within the cell. These enzymes facilitate the exchange of phosphate groups between different nucleoside diphosphates (e.g., GDP to GTP) and triphosphates (e.g., ADP to ATP). This exchange is critical for the synthesis of nucleic acids and the proper function of many cellular processes.During glycolysis, glucose is first phosphorylated by hexokinase (or glucokinase in the liver) using ATP. The phosphate group from ATP is transferred to glucose, forming glucose-6-phosphate. Glycolysis proceeds through a series of other enzymes and steps, eventually leading to the synthesis of ATP by substrate-level phosphorylation. Oxidative phosphorylation also generates ATP but does so using a different mechanism involving the electron transport chain and chemiosmotic gradient across the mitochondrial membrane.