De Duves Thioester World

The discovery of the deep sea hydrothermal systems, and the sulphur-metabolising bacteria which live in them, caused some researchers to look more closely at the element sulphur. It seemed obvious to consider a link between sulphur bacteria— primitive life forms—and the emergence of the simplest forms of life, de Duve, 1974 Nobel Prize winner for medicine, joined the ranks of the biogenesis researchers in the 1980s. 

The physiologist de Duve concentrated his efforts on a material link between the prebiotic phase of the primeval Earth and the state of development at which RNA (or a similar type of molecule) determined the further progress of the evolution process. In particular, this connecting link needed to have been able to transfer chemical energy, since without such a procedure, the RNA synthesis appears impossible. The molecular species which Christian de Duve favours for this important function is that of the thioesters. The exact reasoning as to why this is the case is discussed in detail in his book Vital Dust Life As a Cosmic Imperative (de Duve, 1996). 

The importance of the thioesters was realized at the beginning of the 1950s by Theodor Wieland from the University of Frankfurt am Main (Wieland and Pflei-derer, 1957), who used aminoacyl mercaptans as activated amino acids in peptide syntheses (see Sect. 5.3). Thus, 30 years later, this area of basic research came to be useful for prebiotic chemistry. 

then at the Salk Institute in San Diego, was able to form high-energy thioesters from glycerinealdehyde and A-acetylcysteine. The reaction occurred under anaerobic conditions, at pH 7, in an aqueous solution of sodium phosphate. Of the aldehyde, 0.3% was converted to the lactoyl thioester per day of reaction (Weber, 1984). 

Three years previously, Weber had been able to obtain the thioester N, 5-diacetyl-cysteine from UV irradiation of an aqueous solution of acetaldehyde and AjA -diacetylcysteine (Weber, 1981). 

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