Hexokinase catalyzes the first step of glycolysis by phosphorylating glucose to glucose 6‑phosphate. In red blood cells, hexokinase has a Michaelis constant, K M , KM, of approximately 50 μM, 50 μM, and the substrate concentration, [ S ] , [S], is equal to the blood glucose concentration. Calculate the blood glucose concentration that would yield a hexokinase reaction velocity, V 0 , V0, equal to 90 % 90% of its maximum reaction velocity, V max . Vmax. Express your answer in millimolar ( mM ) (mM) using two significant figures. blood glucose concentration: mM mM What does this result tell you about how hexokinase functions at a normal blood glucose concentration of 3.6 mM to 6.1 mM? 3.6 mM to 6.1 mM? a. It functions at close to its V max Vmax because nearly all the active sites are saturated with substrate. b.It functions at about half its V max Vmax because about half the active sites are saturated with substrate. c. It functions above its V max Vmax because the active sites are supersaturated with substrate. d. It functions at a minimal level because very few active sites are saturated with substrat