2576-67-2Relevant academic research and scientific papers
Thermodynamic Properties of Peptide Solutions Part 6. The Amino Acid Side-chain Contributions to the Partial Molar Volumes and Heat Capacities of some Tripeptides in Aqueous Solution
Reading, Julia F.,Hedwig, Gavin R.
, p. 3117 - 3123 (2007/10/02)
Limiting partial molar volumes, V02, and partial molar heat capacities, C0p,2, have been determined for the tripeptides glycyl-L-valylglycine, glycyl-DL-serylglycine and the D and L isomers of glycylleucylglycine in aqueous solution at 298.15 K.These V02 and C0p,2 results, in conjunction with those for glycylglycylglycine, were used to estimate the contribution of the side chains to the thermodynamic properties.The results obtained are compared with those estimated using V02 and C0p,2 data for amino acids and dipeptides.The comparison suggests that the tripeptides of sequence glycyl-X-glycine are reasonable models for estimating the contribution to the thermodynamic properties of proteins made by solvent-accessible side chains.
Model studies of competing hydrolysis and epimerization of some tetrapeptides of interest in amino acid racemization studies in geochronology
Moir, Michael E.,Crawford, Robert J.
, p. 2903 - 2913 (2007/10/02)
The processes of epimerization of individual peptide units in proteins and the concurrent cleavage of peptide bonds are modelled by heating some tetrapeptide and tetrapeptide derivatives to 148.5 deg C in pH 6.8 phosphate buffer.An excess of D-proline was observed during the heating of L-propyl-L-leucylglycylglycine.The D/L ratio of proline attains a maximum value of 2.1 after 90 minutes.The excess D-proline is attributed to the formation of a 2.3:1 mixture of diketopiperazines cyclo-(D-propyl-L-leucyl) and cyclo-(L-prolyl-L-leucyl).These two species account for most of the leucine and proline in the final mixture after the tetrapeptide is no longer detectable.Only small amounts of prolylleucine can be detcected after 50 hours.It is suggested that the above tetrapeptide undergoes internal aminolysis.Leucine in the tetrapeptide glycyl-L-leucylglycylglycine racemizes three times faster than in L-propyl-L-leucylglycylglycine.This demonstrates that an amino acid residue in a peptide chain does have an effect upon the rate of epimerization of a neighbouring peptide residue.A discussion of the geochemical implications of the results is included.
