For example, consider that neither the structure nor the proportion of the amino acids used for dating coral, ostrich eggshell, or snail shells is known. Using"Amino acid dating cannot obtain the age of the material purely from the data itself.
Again, those like Goodfriend and Hare (1995) have pointed out the "difficulties in estimating the amount of asparagine in proteins and reminded researchers of the dangers of extrapolating from the behaviour of pure Asn in solution at high temperature, to the behaviour of Asn in proteins associated with biominerals at ambient temperature . The rate of racemization can not be standardized by itself because it is too changeable.
So, by examining how many have shifted, one can estimate the age of the sample.
Gould and Goodfriend used this to date some snails.
The authors of this particular paper went on to suggest that, "As conformation strongly influences the rate of Asu [cyclic succinimide] formation and hence Asx [aspartic acid asparagine] racemization, the use of extrapolation from high temperatures to estimate racemization kinetics of Asx in proteins below their denaturation temperature is called into question . In the position carboxyl to asparagine in the peptide the replacement of glycine with a bulky amino acid such as proline or leucine resulted in a 33-50-fold decrease in the rate of deamidation"Hydrolysis, or the process of breaking down a protein into smaller and smaller fragments, clearly affects the rate of racemization.Anyway, I'd be interested to know, if one extrapolates known (laboratory measured) rates of racemization back in time, what kind of a check does this give on Carbon 14 and other dating methods. Amino acid geochronology is a relative dating technique able to span the whole Quaternary. Intra-crystalline protein diagenesis (Ic PD) in Patella vulgata. (To hear a radio interview with George, visit The only other animals with similarly long life spans are the giant tortoise and the giant clam, which some have claimed can live about 150 and 220 years, respectively.An article in the Dec 13, 1996 issue of Science, page 1842, discusses dating based on the amino acid racemization technique. ) form, but with time some transform to the D (right) form.