Median kcat/KM number for the entire data set of enzymes and natural substrates

Range ~10^5 M^-1×sec^-1
Organism Generic
Reference Bar-Even A. et al., The moderately efficient enzyme: evolutionary and physicochemical trends shaping enzyme parameters. Biochemistry. 2011 May 31 50(21):4402-10. doi: 10.1021/bi2002289. p.4403 right column 3rd paragraphPubMed ID21506553
Method "Here [investigators] describe a global view of enzyme parameters with the aim of highlighting the forces that shape the catalytic efficiency of enzymes."
Comments "The median turnover number for the entire data set of enzymes and natural substrates is ~10 s^-1 (Figure 1A BNID 111411), where most kcat values (~60%) are in the range of 1-100 s^-1. These rates are orders of magnitude slower than the textbook examples of fast enzymes [e.g., carbonic anhydrase (Figure 1A)], let alone compared to the theoretical limit of 10^6-10^7S^-1. [refs 6,1] The median kcat/KM is ~10^5 M^-1×S^-1 (Figure 1B), where most kcat/KM values (~60%) lie in the range of 10^3-10^6M^-1×S^-1, orders of magnitude below the diffusion limit."
Entered by Uri M
ID 111412