How do I make a Lineweaver-Burk (Double Reciprocal) Plot?
1 Answer
The equation for the Lineweaver-Burk plot is gotten by doing as the alternative name suggests... taking the reciprocal.
GENERAL REACTION
LINEWEAVER-BURK PLOTS WITHOUT INHIBITOR
#\mathbf(v_0 = (v_max[S])/(K_M + [S]))# where
#v_max = k_2[E]_"total"# ,#k_2# is the observed rate constant for the conversion of the enzyme-substrate complex to the free enzyme and the product, and#[E]_"total"# is the total concentration of the enzyme (free, complexed, whatever).
So naturally, you reciprocate as follows:
#1/(v_0) = (K_M + [S])/(v_max[S])#
#1/(v_0) = (K_M)/(v_max[S]) + cancel([S])/(v_maxcancel([S]))#
#color(blue)(1/(v_0) = (K_M)/(v_max)1/([S]) + 1/(v_max))#
Once you plot
Of course, this is assuming that there is no inhibitor. If there is an inhibitor, then you can have either of the following reactions:
ENZYME INHIBITION
#\mathbf(E + I rightleftharpoons EI)#
#K_I = ([E][I])/([EI])# where
#K_I# is the dissociation constant for the#EI# complex into the free enzyme and the inhibitor.
#\mathbf(ES + I rightleftharpoons ESI)#
#K_I' = ([ES][I])/([ESI])# where
#K_I'# is the dissociation constant for the#ESI# complex into the#ES# complex and the inhibitor.
The resultant Lineweaver-Burk equations are still basically identical, other than the fact that now we'd use
LINEWEAVER-BURK EQUATIONS FOR INHIBITION
Competitive Inhibition (binds only to free enzyme):
#color(blue)(1/(v_0) = (alphaK_M)/(v_max)1/([S]) + 1/(v_max))# where
#alpha = 1 + ([I])/(K_I)# .
Note that here,
Uncompetitive Inhibition (binds only to
#color(blue)(1/(v_0) = (K_M)/(v_max)1/([S]) + alpha/(v_max))# where
#alpha = 1 + ([I])/(K_I)# .
Note that here,
Pure Non-Competitive Inhibition (binds onto enzyme and
#color(blue)(1/(v_0) = (alphaK_M)/(v_max)1/([S]) + (alpha)/(v_max))# where
#alpha = 1 + ([I])/(K_I)# .
Note that here,
Mixed Non-Competitive Inhibition (binds onto enzyme and
#color(blue)(1/(v_0) = (alphaK_M)/(v_max)1/([S]) + (alpha')/(v_max))# where
#alpha = 1 + ([I])/(K_I)# and#alpha' = 1 + ([I])/(K_I')# .
Note that here,