The muscle isozyme of lactate dehydrogenase is inhibited by lactate. Steady state kinetic...

The muscle isozyme of lactate dehydrogenase is inhibited by lactate. Steady state kinetic analysis yielded the following data, with lactate either absent or present at a fixed concentration. loss of NAD+/NADH, Pi, H2O, or H+ has not been shown explicitly. Draw the structures for the intermediates B, F, G, H, and I, and include other reaction participants as needed.

(a) Pyruvate is the substrate whose concentration is varied in one plot, NADH in the other. Identify each. Use an arrow and the appropriate letter (b, c, d, or e) to identify each of the following.

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(b) Reciprocal of Vmax for the uninhibited enzyme.

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 (c) The line representing data obtained in the presence of lactate acting as a competitive inhibitor with respect to the variable substrate.

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 (d) The line representing data obtained in the presence of lactate acting as a mixed inhibitor with respect to the variable substrate.

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 (e) Reciprocal of KMin the presence of lactate acting as a competitive inhibitor.

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 (f) If KMfor NADH is 2 × 10−5 M, which is the most appropriate NADH concentration to use when determining Kmfor pyruvate? 10−7 M, 10−6 M, 10−5 M, 10−4 M, or 10−3 M