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

mais and of humans. Then they established the reaction speed coefficient of aspartic acid for human teeth at 8,29x10"* year"

1

, but they measured it at 7,87xl0-4 year

1 a year later (HELFMAN & BADA 1976). BADA & BROWN (1980) produced a calibrating diagram by plotting In (1+D/L)/(1-D/L) against time. They found a satisfactory level of conformity between the actual age data and the data estimated on the basis of amino-acid racemisation. GlLLARD et al. (1990) analysed the D-Asp content of molars and premolars. They failed to establish significant differences between the D-Asp contents of the same teeth when taking samples from several parts of their crowns and roots. OHTANI & YAMAMOTO (1992) found significant differences between estimated and actual ages when comparing the D-Asp contents of dental enamel and dentin substance. They detected that racemisation (k

Asp

: 5.75x1

0"

4 year"') is much faster in dentin than in enamel (k

Asp

: 4.47x 10^ year"

1

). They concluded that age could be more accurately estimated on the basis of dentin (±3 years) than on the basis of enamel (±2-11 years). They also calculated post-mortal reaction speed coefficients for an average temperature of 15 °C (dentin: k

A : 9.70x1

0"

8 year"

1 and enamel: k

Asp

: 1.330x1

0"

7 year

1

). RlTZ et al. (1993) analysed the dentin substance of third molars' roots and they arrived at the conclusion that racemisation of the root's dentin was somewhat different to that of the crown's dentin. They produced a special calibration diagram for those cases where age has to be determined but the crown substance was damaged or impaired. They established that the degree of Asp racemisation was multiplied in acid solvent proteins compared to non-acid solvent ones. OHTANI (1994) examined Asp racemisation on central and lateral incisors, on first and second molars and he also treated the averages of these. He found a close correlation of actual ages and D/L Asp ratios. OHTANI concluded that racemisation within deciduous teeth was an excellent indicator for the estimation of individual age, but racemisation of permanent was far less useful for the same purpose. RlTZ et al. (1995) worked out a biopsical sampling technique for teeth. Thanks to the strictly regulated nature of the sampling process ages estimated on the basis of Asp racemisation presented a very close conformity to actual ages. RlTZ et al. (1995) established a margin of error not larger than ±year for 46.4% of the cases analysed and the error of age estimation never went beyond the ±5 years limit. Recently we could see a dramatic progress of analytic methods but still there is no process that could perfectly separate the enantiomers of all protein constitutive amino acids in a single step. D-Asp was easy to trace and to separate from L-Asp and from other amino acids and the enantiomers of those, and these characteristics made it evidently suitable tools for analytic methods.