Halftime of spontaneous polysaccharide bond hydrolysis at 25°C

Value 4.7e+6 years
Organism Generic
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.940 table 1 Table - link PubMed ID11747411
Method Reaction rates were measured at series of elevated temperatures, following them to completion. The resulting Arrhenius plot, if linear, can then be extrapolated to 25 °C. In much of this work, reaction mixtures were sealed in quartz, heated over various intervals, and then opened for analysis by proton NMR. The vapor pressure of water does not change enough to affect reaction rates significantly, but aqueous samples tend to burst at temperatures above 250 °C (40 atm). Explosions are avoided by placing reaction tubes in water inside a steel bomb, equalizing pressure across the wall of each tube. PTFE vessels must be used for alkaline solutions which attack quartz.
Comments In neutral solution, where glycoside hydrolysis becomes pH-independent (Figure 3), Arrhenius plots yield half-times at 25°C of 5 million and 8 million years for hydrolysis of a- and ß-methylglucosides, respectively. 160 years at 100°C. See table link.
Entered by Uri M
ID 105353