Age determination based on amino acid racemization: A new possibility

Abstract

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.

Epimerization of Cyclic Alanyl-Alanine in Basic Solutions

“…However, in some cases [2][3][4][5] ,racemization has been used to meanboth racemization and epimerization. Epimerization and racemization in amino acids, peptides, and proteinshave been investigated from many viewpoints [2][3][4][5][6][7][8][9][10][11] . Epimerization of aspartic residues in proteins may sometimes increase thehydrophobicity of the proteins, because several diastereomeric peptides composed of D-aspartic residues show higher hydrophobicity than the…”

“…The ver tical axis shows the inverse logarithm of the concentration of the product divided by the initial concentration of the reactant for Homo-L-CP (1) and Hetero-CP (2), and the inverse logarithm of 1 minus the concentration of the product divided by the concentration of initial reactant for Homo-L-LP (6) plus Homo-D-LP (9) and Hetero-LP (7) plus (8). The horizontal axis shows the reaction timein minutes.…”

Egy egyedülálló dél-alföldi löszszelvény malakológiai vizsgálata és a terület felső-würm paleoklimatológiai rekonstrukciója

“…A V. tenuilabris görbéje kiegyenlítettebb, folyamatosan 10-14% között van jelen a mintákban. (Csapó et al 1994(Csapó et al , 1998(Csapó et al , 2008Albert et al 2006). Cikkei alapján a módszer jól használható fosszilis anyagok esetében.…”

Aspartic Acid Racemization Method for Age Estimation in Human Tissues: A Review

“…The change D/L ratio of amino acid during aging can be used to estimate the death time of the organism. The low protein turnover tissue which is usually used for amino acid racemization is teeth and racemization rate is approximately 0.1% per year in the low metabolism tissue like dentine (Csapo et al 1994). Moreover, racemization can be occurred in various structures such as the bones, white matter of brain, artery and eye-lens (Dobberstein et al 2010;Griffin et al 2008a;Johnson & Miller 1997).…”