Origins of life and evolution of the biosphere

, Volume 26, Issue 2, pp 111–129

Was ferrocyanide a prebiotic reagent?

  • Anthony D. Keefe
  • Stanley L. Miller
Article

DOI: 10.1007/BF01809851

Cite this article as:
Keefe, A.D. & Miller, S.L. Origins Life Evol Biosphere (1996) 26: 111. doi:10.1007/BF01809851
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Abstract

Hydrogen cyanide is the starting material for a diverse array of prebiotic syntheses, including those of amino acids and purines. Hydrogen cyanide also reacts with ferrous ions to give ferrocyanide, and so it is possible that ferrocyanide was common in the early ocean. This can only be true if the hydrogen cyanide concentration was high enough and the rate of reaction of cyanide with ferrous ions was fast enough. We show experimentally that the rate of formation of ferrocyanide is rapid even at low concentrations of hydrogen cyanide in the pH range 6–8, and therefore an equilibrium calculation is valid. The equilibrium concentrations of ferrocyanide are calculated as a function of hydrogen cyanide concentration, pH and temperature. The steady state concentration of hydrogen cyanide depends on the rate of synthesis by electric discharges and ultraviolet light and the rate of hydrolysis, which depends on pH and temperature. Our conclusions show that ferrocyanide was a major species in the prebiotic ocean only at the highest production rates of hydrogen cyanide in a strongly reducing atmosphere and at temperatures of 0°C or less, although small amounts would have been present at lower hydrogen cyanide production rates. The prebiotic application of ferrocyanide as a source of hydrated electrons, as a photochemical replication process, and in semi-permeable membranes is discussed.

Key words

FerrocyanideferricyanidePrussian Blueblueprinthydrogen cyanide production ratesprebiotic synthesis

Copyright information

© Kluwer Academic Publishers 1996

Authors and Affiliations

  • Anthony D. Keefe
    • 1
  • Stanley L. Miller
    • 1
  1. 1.Department of Chemistry and BiochemistryUniversity of CaliforniaSan Diego, La JollaUSA
  2. 2.NASA Ames Research Center, M/S 239-4Moffett Field