Question

Can someone please help with questions ii-vi?

6. Many types of cancerous tumors have cells with a high dependence on glycolysis for generating the ATP needed for growth. Even in the presence of oxygen, these cells use glycolysis and lactate fermentation as their main source of ATP. i.) Give a balanced reaction for the reaction catalyzed by the enzyme lactate dehydrogenase (LDH). Give the structures of pyruvate and lactate, and add the names of any additional reactants or products needed to balance the equation. lactate dehydrogenase pyruvate NAD+ lactate ii.) Below is a plot of lactate dehydrogenase kinetics when only pyruvate is limiting. The Vmax for this experiment was found to be 3.50 umol of NAD produced per min. What is the Ky for pyruvate for this enzyme? Determine this value from the graph as accurately as possible.

Answer 1

Answer: (i)

H0 H LDH pyruvate L-lactate но Y NH NADH NAD

Answer: (ii)  K_M = 1/2 * V_max = 3.5/2 = 1.75 micro-mol per minute.

K_M is referred to as the Michaelis constant and is the substrate concentration at which the reaction rate is exactly half of V_max.

Answer: (iii)

K_M = (2/2) = 1 μmol/min

Answer: (iv)

Lactate Dehydrogenase Kinetics vo (umol/min) 0.05 0.1 0.15 [pyruvate) (MM)