Answer to Question #5085 in Biochemistry for saif

Question

The muscle enzyme lactate dehydrogenase is inhibited by lactate. Steady state kinetic
analysis yielded the following data, with lactate either absent or present at a fixed concentration.
(a) Pyruvate is the substrate whose concentration is varied in one pot, NADH in the other. Identify
each. Use an arrow and the appropriate letter (b, c, d, or e) to identify each of the following.
(b) Reciprocal of Vmax for the uninhibited enzyme (on both plots).
(c) The line representing data obtained in the presence of lactate acting as a competitive inhibitor with
respect to the variable substrate.
(d) The line representing data obtained in the presence of lactate acting as a noncompetitive inhibitor
with respect to the variable substrate.
(e) Reciprocal of KM in the presence of lactate acting as a competitive inhibitor.
(f) If KM for NADH is 2x10-5M, which is the most appropriate NADH concentration to use when
determing KM for pyruvate: 10-7M, 10-6M, 10-5M, 10-4M, or 10-3M.