Question

Which glycolytic enzyme uses ATP as a substrate?

A) alcohol dehydrogenase
B) phosphoglucoisomerase
C) aldolase
D) hexokinase
E) triose phosphate isomerase

Answer 1

Hexokinase and phosphofructokinase are the glycolytic enzymes that use ATP as a substrate. Hexokinase acts in the first step of glycolysis, and phosphofructokinase acts further downstream in the pathway.

Step-by-step explanation:

The glycolytic enzyme that uses ATP as a substrate is hexokinase. During the first step of glycolysis, hexokinase catalyzes the phosphorylation of glucose to form glucose-6-phosphate, consuming one molecule of ATP in the process. Another enzyme, phosphofructokinase, also uses ATP later in glycolysis to convert fructose-6-phosphate into fructose-1,6-bisphosphate. These steps are part of the energy investment phase of glycolysis where ATP is utilized to modify glucose, facilitating its subsequent breakdown into pyruvate and the generation of ATP and NADH in later stages.