Question

An enzyme that catalyzes the addition of a phosphate group from ATP to another molecule is called a:

1) Kinase
2) Phosphatase
3) Ligase
4) Isomerase

Answer 1

A kinase is the enzyme that catalyzes the addition of a phosphate group from ATP to another molecule as seen in metabolic processes like glycolysis during substrate-level phosphorylation.

Step-by-step explanation:

An enzyme responsible for catalyzing the addition of a phosphate group from ATP to another molecule is known as a kinase. This process, which involves transferring a phosphate group to a substrate molecule, is a key part of many cellular activities, including the regulation of metabolic pathways and signal transduction. The attachment of a phosphate group often results in a structural change and functional activation or deactivation of the target protein.

For example, the enzyme phosphoglycerate kinase performs a critical step during glycolysis, where it catalyzes the transfer of a phosphate group from 1,3-bisphosphoglycerate to ADP, creating ATP in a process commonly referred to as substrate-level phosphorylation. This step showcases the enzymatic activity of a kinase, distinguishing it from other enzymes like phosphatases, which remove phosphate groups, ligases, which join molecules together, and isomerases, which convert molecules into their isomers.