title: Massive thermal acceleration of the emergence of primordial chemistry, the incidence of spontaneous mutation, and the evolution of enzymes.
abstract: Kelvin considered it unlikely that sufficient time had elapsed on the earth for life to have reached its present level of complexity. In the warm surroundings in which life first appeared, however, elevated temperatures would have reduced the kinetic barriers to reaction. Recent experiments disclose the profound extent to which very slow reactions are accelerated by elevated temperatures, collapsing the time that would have been required for early events in primordial chemistry before the advent of enzymes. If a primitive enzyme, like model catalysts and most modern enzymes, accelerated a reaction by lowering its enthalpy of activation, then the rate enhancement that it produced would have increased automatically as the environment cooled, quite apart from any improvements in catalytic activity that arose from mutation and natural selection. The chemical events responsible for spontaneous mutation are also highly sensitive to temperature, furnishing an independent mechanism for accelerating evolution.
authors.affiliation: Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina 27599-7260. Electronic address: water@med.unc.edu.
authors.forename: Richard
authors.initials: R
authors.lastname: Wolfenden
mesh_terms: D055162:Biocatalysis; D004795:Enzyme Stability; D004798:Enzymes / Q000737:chemistry / Q000235:genetics*; D019143:Evolution, Molecular; D006207:Half-Life; D006801:Humans; D007700:Kinetics; D009154:Mutation; D013816:Thermodynamics
chemical_list: D004798:Enzymes
keywords: Energy of Activation; Enzyme; Enzyme Catalysis; Enzyme Inhibitor; Enzyme Mechanism; Heat of Activation; Spontaneous Mutation; Tempo of Mutation; Thermodynamics