M. Járó - L. Költő szerk.: Archaeometrical research in Hungary (Budapest, 1988)
Dating - CSAPÓ János, KÖLTŐ László , PAP Ildikó: Archaeological age determination based on the racemization and epimerization of amino acids
CSAPÓ János*, KÖLTŐ László**, PAP Ildikó*** ARCHAEOLOGICAL AGE DETERMINATION BASED ON THE RACEMIZATION AND EPIMERIZATION OF AMINO ACIDS Abstract - The authors have adapted a method for determining the ages of fossils, using the method of isoleucine and other protein amino acid racemizations. By measuring D-alloisoleucine bone samples pver 500ÙD years, by the fast racemization amino acid D and L versions, followed by ion exchange column-chromatography separation-with chiral silica gel layer the ages of bone findings between 5000 and 50000 years could be determined with the error of the analytical method (for D-alloisoleucine ±5%, and ±15-20% for the other amino acids). A proposal is made for determining bone samples with the approximate age of 1000 years, with the possible application of amino acids with sulphur and with fatty acids. 1. Introduction In 1860 Pasteur examined asparagjne from the point of view of optical activity. The asparagine was derived from wild pea. In his further works he established that most of the chemical compounds playing an important role in the lives of animals and plants are asymmetric; and only asymmetrical compounds have optical activity. Terentev and Klabunovskii (1957) stated that life cannot be and has never existed without any molecular asymmetry. There must be some relationship between optical activity and life, as all proteins are built up of only L—enantiomer amino acids, while the configuration of natural sucrose is D. In various experiments simulating the creation of life, the simulation of the primitive reduction atmosphere yielded the synthetization of several amino acids. These were, however, racemic, and in these experiments none of the enantiomers was favoured over the others (Stephen-Sherwood and Oró, 1973). In 1908 Van't Hoff, and in 1934 Karagunis and Drikos succeeded in synthesizing optically active compounds with the aid of circularly polarized light. The problem with these experiments was, however, that polarized light appears in nature only in very extreme circumstances, e. g. as a response to y radiation emitted during ß decomposition (Goldhaber et al. 1957). Several scientists have reported on the synthesis of D- and L-amino acids or on their decomposition during their bombardment with ß particles or with polarized electrons. In 1968 Ponnamperuma and Gabel found during the examination of some geological deposits that optically active organic molecules are definite proof of the existance of life during the formation of the deposits. This of course holds only if the optically active organic compounds have not racernized in the meantime. During the past 15-20 years several scientists have examined the amino acid contents of meteorites and lunar deposits. Several kinds of amino acids were traceable in these materials, which undoubtably were formed abiotically; however the optical activity measurements always yielded a negative result . * Stock-Breeding Faculty of the Agricultural University H-7400 Kaposvár, Dénes-major 2. ** Directorate of the Museum of the County of Somogy H-7401 Kaposvár, P.O.B. 71. '** Anthropological Department of Hungarian Natural History Museum H-1062 Budapest, Bajza u. 39.
