The enzyme that catalyses the very first step of glycolysis is:

1. The first step traps glucose in the cell by adding a phosphate to it. 2. The enzyme responsible acts on six-carbon sugars generally. 3. The first step in glycolysis is catalyzed by hexokinase, an enzyme with broad specificity that catalyzes the phosphorylation of six-carbon sugars. 4. Aldolase acts at step four and pyruvate kinase at the very last step. _Source: OpenStax Biology for AP(R) Courses (CC BY 4.0), Ch 7 'Cellular Respiration', sections 7.1-7.7_