Boundary to enzyme turnover rate suggested by theoretical limitations

Range 10^6 - 10^7 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.4402 right column top paragraphPubMed ID21506553
Primary Source [6] enkovic, S. J., and Hammes-Schiffer, S. (2003) A perspective on enzyme catalysis. Science 301, 1196 – 1202. [17] Hammes, G. G. (2002) Multiple conformational changes in enzyme catalysis. Biochemistry 41, 8221 – 8228.PubMed ID12947189, 12081470
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 "There are also several known physicochemical constraints that set boundaries to kinetic parameters. [refs 15,16] For example, theoretical limitations suggest that kcat is unlikely to be higher than 10^6-10^7S^-1. [primary sources] Furthermore, the apparent second-order rate for a diffusion-limited enzyme-catalyzed reaction with a single low-molecular mass substrate (kcat/KM) cannot exceed ~10^8-10^9S^-1M^-1. [refs 18,19]"
Entered by Uri M
ID 111409