RCSB Protein Databank

Brenda-enzymes for collected enzyme data

aa analysis - from Nature

Inhibitor Definitions
Ki (M) - Dissociation constant. Concentration that leads to occupation of half of the active sites.
IC50 (M) - Concentration that lowers enzyme activity to half of the original.

Ligand efficiency: free energy of binding divided by number of atoms.

          Vmax [S]  
v0 =   Km + [S]

Vmax = kcat [E]0

Vmax (M s-1) is the maximum rate of the reaction mixture - it is dependant on enzyme concentration!
kcat (s-1) is the no. of molecules reacted per second per enzyme molecule when the substrate is at saturating concentration.
Km (M) in the substrate concentration responsible for 50% of the maximum velocity (Vmax).

Subpages (2): Km Reaction order