Inhibitor effect on enzyme

Discussion in 'General Science' started by boks, Nov 25, 2008.

  1. boks

    Thread Starter Active Member

    Oct 10, 2008

    I'm asked to calculate V[sub]max[/sub] and K[sub]M[/sub] from this, with and without the inhibior, and answer what kind of inhibitor it is.

    I have plotted 1/ vs 1/V[sub]0[/sub] here:


    The x-intercept is -1/K[sub]M[/sub]. The value I get is -1/K[sub]M[/sub]=-4E4, so that K[sub]M[/sub]=25E-6. Does this mean that K[sub]M[/sub]=25E-6 M? My book says 20-24 M. Of course, I might have been unaccurate in drawing the graph, but why do I miss by a factor of 1E6?
  2. jpanhalt


    Jan 18, 2008
    A Km of 24 molar is pretty high in my experience. By comparison, pure water is 55.5 molar. Are you sure the book's value is not the typo? I didn't do the calculations, but from the data in the table, a Km in the range of 10E-6 M seems more reasonable.