In muscle cells, which enzyme would act as the rate-limiting step to regulate entry of products from all three dietary disaccharides into glycolysis?

Answer: Phosphofructokinase-1

Explanation:

The phosphofructokinase-1 is an enzyme that mediate the conversion of fructose-6 phosphate into another sugar fructose-1,6 bisphosphate. Thus this enzyme is enzyme act as a rate enzyme to regulate the cycle. The three sugar or dietary disaccharides undergoes the glycoloysis mediated by the phosphofructokinase-1.

This enzyme is able to regulate the glycolysis by allosteric inhibition. This way the cell can either increase or decrease the rate of glycolysis in relation to the requirement of energy by the cell.