The Michaelis–Menten relationship can be expressed in several algebraically equivalent linear forms used for plotting. Which statement correctly summarizes these alternative forms?

Difficulty: Medium

Correct Answer: All of these

Explanation:


Introduction / Context:
Although the canonical Michaelis–Menten equation v = (Vmax * [S]) / (Km + [S]) is nonlinear, several linear rearrangements facilitate parameter estimation and diagnostic plotting. Three classic forms are Lineweaver–Burk, Hanes–Woolf, and Eadie–Hofstee.


Given Data / Assumptions:

  • Symbols: r (or v) for rate, Cs (or [S]) for substrate, rmax (or Vmax) for maximum rate.
  • Steady-state, initial-rate conditions apply.
  • Algebraic rearrangements preserve equivalence if performed correctly.


Concept / Approach:
Demonstrate each rearrangement starting from r = (rmax * Cs) / (Km + Cs) and show equivalence to one of the standard plotting lines.


Step-by-Step Solution:

Lineweaver–Burk: Take reciprocals → 1/r = (Km + Cs)/(rmax * Cs) = (1/rmax) + (Km/(rmax * Cs)).Hanes–Woolf: Multiply both sides by (Km + Cs)/r → Cs/r = (Cs/rmax) + (Km/rmax).Eadie–Hofstee: Multiply both sides by (Km + Cs)/Cs → r = rmax - (Km * r / Cs).All three are algebraically equivalent to the original Michaelis–Menten expression.


Verification / Alternative check:
Fitting the same data with these transformations yields identical parameter values in the absence of error; differences in practice reflect error-weighting, not algebraic inequivalence.


Why Other Options Are Wrong:

  • Each individual linear form is valid; therefore “None of these” is incorrect.


Common Pitfalls:
Confusing sign conventions or mixing symbols; ensure r corresponds to v and Cs to [S]. Also note that linearizations can distort error structure; modern practice often fits the untransformed nonlinear model.


Final Answer:
All of these

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