Substrate concentration and reaction rate

How do we measure rate of chemical reactions?

Appearance of product or disappearance of substrate

Steady state

[ES] stays the same, formation of complex= formation of product

Assumptions made when deriving rate constant equations?

• Steady stat conditions apply

• Initial [P]=0 no reverse at the start

• Relative concentrations [S]> > [E]- ignore change in substrate concentration

• Formation of product-vo=k2[ES]- first order rate equation, k2=kcat (initial velocity)

What determines maximum velocity

Total enzyme and Kcat

Relationship between Km and Vmax?

Km= Vmax/2

Hyperbolic curve, Km in [S]

Lineweaver-Burk plots

Generates a hyperbolic relationship between [S] and Vmax

Slope: Km/Vmax

Y-intercept: 1/Vmax

Double reciprocal plot

Defined by lineweaver Burke equation- linear plot, same slope and y intercept values

x-intercept= -1/Km