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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.The rate itself of hydrolysis "depends on the strength of the individual peptide bonds, which in turn is determined by the characteristics of the amino acids on either side of the bond, the presence of water and the temperature."All of these are confounding factors, which, if not known exactly over extended periods of time, would play havoc with any sort of age determinations.When there are both equal numbers of dextrorotating and levorotating molecules, the net optical rotation of a racemate is zero.Racemate may have different physical properties from either of the pure enantiomers because of the differential intermolecular interactions.As a matter of fact, the basis of this method had been discovered earlier and had been reported in a series of papers published by Hare, Mitterer and Abelson in 1967, 1968, and 1969.

2.8 Racemization During Peptide Synthesis One of the most serious problems encountered in early peptide synthesis was partial racemization of the incorporated amino acids. NH2 NH2 Scheme 13.3 Racemization of (R)-phenylethylamine with base at high temperature.In general, only one form of a chiral molecule will participate in biochemical reactions while the other simply does not participate or can cause side-effects.At a widely publicized news conference in August of 1972, Dr.1 Racemization of (S)-9 using 1 mole of various bases. v) Racemization was very rapid in the presence of alkoxides. indicated 0.85% racemization when triethylammonium salts were used, but no racemization with tetrabutylammonium salts.A catalytic amount of potassium tert-butoxide (as low as 5 mol-%) was sufficient for ... The four-component condensation method has been used in the preparation of a cyclic eledoisin analogue and ...