Journal of Molecular Evolution

, Volume 20, Issue 1, pp 38–51

Evolution of catalytic proteins

On the origin of enzyme species by means of natural selection
  • Henrik Kacser
  • Richard Beeby

DOI: 10.1007/BF02101984

Cite this article as:
Kacser, H. & Beeby, R. J Mol Evol (1984) 20: 38. doi:10.1007/BF02101984


It is believed that all present-day organisms descended from a common cellular ancestor. Such a cell must have evolved from more primitive and simpler precursors, but neither their organization nor the route such evolution took are accessible to the molecular techniques available today. We propose a mechanism, based on functional properties of enzymes and the kinetics of growth, which allows us to reconstruct the general course of early enzyme evolution. A precursor cell containing very few multifunctional enzymes with low catalytic activities is shown to lead inevitably to descendants with a large number of differentiated monofunctional enzymes with high turnover numbers. Mutation and natural selection for faster growth are shown to be the only conditions necessary for such a change to have occurred.

Key words

Enzyme evolution Natural selection Multifunctional enzymes Gene duplication Enzyme specificity Metabolic evolution 

Copyright information

© Springer-Verlag 1984

Authors and Affiliations

  • Henrik Kacser
    • 1
  • Richard Beeby
    • 1
  1. 1.Department of GeneticsUniversity of EdinburghEdinburghScotland