Question 23.1: How do the names of the enzymes involved in the first two st...
How do the names of the enzymes involved in the first two steps of glycolysis relate to the reactions involved?
ANALYSIS Look at the names of the enzymes and the reactions. Also recall the enzyme classification scheme from Chapter 19 ( 
, p. 597)
In the first reaction, a phosphoryl group is added to glucose. The enzyme name is hexokinase; kinase because kinases transfer phosphoryl groups, and hexo– for a hexose sugar as the substrate. In the second reaction glucose 6-phosphate is rearranged to fructose 6-phosphate by phosphoglucose isomerase. This enzyme belongs to the enzyme class isomerases, enzymes that rearrange molecules to an isomer of the original molecule. The phosphoglucose part of the name tells us that a phosphorylated glucose molecule will be rearranged; inspection of the reaction shows this is true.