Matskási István (szerk.): A Magyar Természettudományi Múzeum évkönyve 93. (Budapest 2001)
Csapó, J., Bernert, Zs. , Csapó, Zs. , Pohn, G. , Csapó-Kiss, Zs. , Költő, L. , Szikossy, I. ; Némethy, S.: Introduction of amino acid racemisation based age estimation into paleoanthropological [sic] research
was represented by 39 individuals from this 65 (60%), the maturus group by 22 persons (34%), the senium by 4 people (6%). Less than 5% of this historical population survived to their 60th years (BERNÉRT 1996b), and they lost almost all their teeth for this old age. This was the reason why the age group senium was represented by such a low percentage within the sample. There were two men (one of 25-34 years, one of 40-49 years) and one woman whose age could be estimated only within a 10 years interval because of the poor preservation of their remains. Not all the selected age determination methods could be applied for all individuals because of the incomplete preservation of the skeletons (Table 2). Naturally at least partial preservation of the sets of teeth was a prerequisite of dental enamel sampling. Root transparency and wear of teeth could be observed on almost all persons examined. Bad preservation of the skeletons made the application of other age estimation methods possible only in a smaller number of cases. Preparation ofteeth -The protein content of dental dissections was scored by Kjel-Foss rapid nitrogen analyser. The amino acid composition of teeth was measured Labor MIM amino acid analyser, D- and L-amino acid contents were measured by Hitachi Merck LaChrom high performance liquid Chromatograph. Proteins and all amino acids were identified by routine procedure according to accepted standards. D- and L-amino acid enantiomers were separated and identified by the following method: Pyrex reusable hydrolysis tubes were used for the hydrolysis of proteins. In the process of protein hydrolysis we filled 20-50 mg of compound into the Pyrex hydrolysis tubes that were washed with hydrochloric acid and twice distilled water before. 8 cm 3 of 6M hydrochloric acid was added to each sample and nitrogen was bubbled through the system by a glass capillary tube. Hydrolysis tubes were immediately sealed after nitrogen bubbling, and then hydrolysis was carried out with 6M hydrochloric acid on 110 C° for 24 hours, on 160 C° for 30 and on 170 C° for 45 minutes. More than one methods of hydrolysis were necessary because we wanted to determine which one of them produced the smallest level of racemisation. It was an important consideration as D-amino acids could also be produced as by-products in the process of racemisation and this could significantly modify the accuracy of calibration. Our earlier experiments (CSAPÓ et al. 1997) indicated that protein hydrolysis carried out on a higher temperature but for a shorter time produced a lower level of racemisation. Therefore we chose this way for our present series of experiments. Tubes were cooled to room temperature after completing hydrolysis, hydrochloric acid was removed by liophylisation, and the remaining substance was dissolved in 0.01 M hydrochloric acid. Finally, the hydroly satum was filtered and kept on -25 °C until the titration of D and L amino acids.
