Varga Máté - Szentpéteri József (szerk.): Két világ határán. Természet- és társadalomtudományi tanulmányok a 70 éves Költő László tiszteletére - A kaposvári Rippl-Rónai Múzeum közleményei 6. (Kaposvár, 2018)
Csapó János: Új módszer a fosszilis csontok korának meghatározására az aminosavak racemiációja alapján
ÚJ MÓDSZER A FOSSZILIS CSONTOK KORÁNAK MEGHATÁROZÁSÁRA 45 AZ AMINOSAVAK RACEMIZÁCIÓJA ALAPJÁN New method for the age determination of fossilized bones based on amino acid racemization JÁNOS CSAPÓ When using to traditional protein hydrolysis, racemization was 1,2-1,6 times as high as that obtained at high temperatures (160-180 °C), under conditions ensuring total hydrolysis of the protein. This lower degree of racemization may be explained by the fact that, at high temperatures, the protein hydrolyses more rapidly into free amino acids and the racemization of free amino acids is considerably slower that of amino acids bound in polypeptides. Therefore high temperature hydrolysis (at 160 °C for 45 to 60 minutes, at 170 °C for 30-45 minutes and 180 °C for 30 minutes) are recommended for those who would like to hydrolyse the protein for short times and to determine the degree of racemization occurring in the polypeptide chain, but do not wish to use enzyme hydrolysis. After developing protein hydrolysis method with low racemization, a method has been developed to determine the age of fossil bone samples based on amino acid racemization (AAR). Approximately one hundred fossil bone samples of known age from Hungary were collected and analysed for D- and L- amino acids. As the racemization of amino acids is affected by temperature, pH, metal content of the soil, and time passed since death, these factors were eliminated by comparing the estimated age to age determined by the radiocarbon method. Determining the D- and L- amino acid contents in samples of known age, determining the half life of racemization, and plotting the D/L ratio as a function of time, calibration curves were obtained. These curves can be used for the age estimation of samples after determining their D- and L- amino acid content. The D/L ratio for 2 to 3 amino acids was determined for each sample and the mean value of estimated ages based on calibration curves was considered to estimate age of the fossil samples.
