There are four enzymes that can catalyze the first step of glycolysis. They are hexokinases I, II and III and glucokinase hexokinase IV). Hexokinases I, II and III have K_mvalues near 0.1 mM. Glucokinase has a K_mrange of 2-5 mM. If after a heavy meal the blood glucose level rises to 8 mM which statement will be true?

Question

Quizplus · Accepted Answer

Hexokinases I, II, and III have low Km values and are saturated at low glucose concentrations, so they are catalyzing at their maximum rate. Glucokinase, with a higher Km, is not saturated and can still increase its activity as glucose levels rise.

There Are Four Enzymes That Can Catalyze the First Step