kcat/Km and knon values for some key reactions at 25 °C

Range Figure - link
Organism Unspecified
Reference Wolfenden R, Snider MJ. The depth of chemical time and the power of enzymes as catalysts. Acc Chem Res. 2001 Dec34(12):938-45. p.941 fig.6PubMed ID11747411
Primary Source See pointers to refs beneath Table - link
Comments "As a measure of catalytic proficiency and a benchmark for the design of potential transition-state analogue inhibitors, the value of Ktx ([transition-state binding affinity,] obtained by dividing the rate constant of the uncatalyzed reaction (knon) by kcat/Km: see Figure 2) is of special interest. In Figure 6, the length of each vertical bar represents the value of Ktx. These values range from 10^-8 to 10^-23 M, setting an upper limit (Figure 2) on the dissociation constant of the enzyme's complex with the altered substrate in the transition state." knon=non enzymatic rate constant
Entered by Uri M
ID 107178