||One of the ways biochemists characterize enzymes is to study the rates of enzyme-catalyzed reactions, a field known as enzyme kinetics. The study of enzyme kinetics provides researchers with clues as to how enzymes work. In 1913, Leonor Michaelis and Maud Menten derived a rate law that governs enzyme kinetics.
Michaelis-Menten enzyme kinetics can be modeled by the following equation,
where V represents the reaction velocity, Vmax represents the maximum reaction velocity, Km represents the Michaelis-Menten constant, and [S] represents the substrate concentration.
Note of caution
This equation assumes that during the reaction the concentration of the enzyme-substrate complex remains constant and is lower than the concentrations of unbound substrate. These conditions are known as steady-state.
Looking at the equation, one can readily see that the velocity of the reaction, V , is dependent on the substrate concentration,
[S]. In fact, the Michaelis-Menten equation is a rational function. As rational functions can be difficult to work with graphically, the
Michaelis-Menten equation can be transformed into a linear equation by taking
the reciprocal of both sides as,
This new equation is called the Lineweaver-Burk equation after the researchers who derived it in 1934. The Lineweaver-Burk equation is a linear equation, where 1/V is a linear function of 1/[S]
instead of V being a rational function of [S]. The Lineweaver-Burk equation
can be readily represented graphically to determine the values of Km and Vmax.
Now use the Lineweaver-Burk equation to answer the following questions:
Determine the slope of the line represented by the Lineweaver-Burk equation.
Determine the 1/V -intercept of the Lineweaver-Burk equation.
Given a Lineweaver-Burk plot, determine the Vmax of a particular enzyme.
Given a Lineweaver-Burk plot, determine the Km of a particular enzyme.
Determine the 1/[S]-intercept of the Lineweaver-Burk equation.
Compare a Lineweaver-Burk plot to a Michaelis-Menten plot for the same data set.