Massive Thermal Acceleration of the Emergence of Primordial Chemistry, the Evolution of Enzymes, and the Tempo of Spontaneous Mutation [Molecular Biophysics]

September 10th, 2014 by Wolfenden, R.

Kelvin considered it unlikely that sufficient time had elapsed on the earth for life to have reached its present level of complexity. But in the warm surroundings in which life first appeared, elevated temperatures would have increased the rates of all chemical reactions. This review describes the startling extent to which particularly slow reactions are accelerated by elevated temperatures, collapsing by several orders of magnitude the time that would have been required for early events in primordial chemistry, before the advent of enzymes. In a potential scenario for the early evolution of enzymes, several artificial catalysts have been shown to catalyze reactions by lowering their enthalpies of activation. If a primordial enzyme exhibited that behavior, it would have produced a rate enhancement that increased automatically as the environment cooled, quite apart from any improvements in catalytic activity that arose from mutation and natural selection. Perhaps echoing that evolutionary origin, a pronounced majority of present-day enzymes act as enthalpic catalysts. Finally, several of the chemical events that are believed to be responsible for spontaneous mutation have been shown to be highly sensitive to temperature, furnishing an independent mechanism for the thermal acceleration of evolution during the early history of the earth.
  • Posted in Journal of Biological Chemistry, Publications
  • Comments Off on Massive Thermal Acceleration of the Emergence of Primordial Chemistry, the Evolution of Enzymes, and the Tempo of Spontaneous Mutation [Molecular Biophysics]