59095-76-0Relevant articles and documents
Neighboring Residue Effects: Evidence for Intramolecular Assistance to Racemization or Epimerization of Dipeptide Residues
Smith, Grant Gill,Evans, Robert C.,Baum, Rocky
, p. 7327 - 7332 (2007/10/02)
Dipeptides, their methyl esters, diketopiperazines (DKP), and N-substituted derivatives were racemized at high temperatures (approximately 120 deg C) in aqueous phosphate buffered solutions at pH values close to pH of maximum racemization (approximately 8).The racemization of the dipeptides Ala-Gly and Gly-Ala followed reversible first-order kinetics.The initial rate of racemization of DKP was very fast but soon slowed down, supposedly due to hydrolysis.The resulting rate was similar to that of the dipeptides.Esters of dipeptides followed racemization patterns similar to DKP.The racemization rate constants of the dipeptides studied were shown to be independent of the concentration of the dipeptide and the concentration of buffer.A carboxy-terminal proline residue greatly increased the rate of racemization (epimerization) of the amino-terminal residue.Increasing the basicity of the N-terminal amino acid residue increased the rate of racemization (or epimerization) of the C-terminal residue unless the C-terminal was sterically hindered as the Ile and Val.Decreasing the basicity of the N-terminal amino acid residue decreased racemization or epimerization for nonhindered C-terminal amino acids.These results support the influence of neighboring groups in the racemization or epimerization of dipeptides.DKP formation is a competing reaction allowing racemization or epimerization in dipeptides.Dipeptide racemization or epimerization is proposed to be the result of combination of intramolecular base assistance and DKP formation.
Metal Complexes with Biologically Important Ligands, XXXVII. Peptide Synthesis at Platinum(II) Ions
Beck, Wolfgang,Bissinger, Herbert,Castro, Thais Castrillo de,Olgemoeller, Luitgard,Purucker, Bernhard
, p. 3135 - 3142 (2007/10/02)
A series of platinum(II) complexes cis- and trans-Cl2Pt(peptide ester)2 (1-16) has been obtained via peptide synthesis at the free carboxylic group of N-coordinated α-amino acids, using a water-soluble carbodiimide as coupling agent.The amino protecting platinum(II) is removed via substitution of the dipeptide ester by 1,2-bis(diphenylphosphino)ethane or, most advantageously, by hydrogenation with hydrogen.Peptide formation and removal of the platinum(II) proceed practically without racemization.
Structure-taste Relationships of Aspartyl Tripeptide Esters
Ariyoshi, Yasuo
, p. 3197 - 3202 (2007/10/02)
A series of twenty four analogues of L-α-Asp-Gly-Gly-OMe has been synthesized in relation to structural features of sweet peptides.The rule in the structure-taste relationships of dipeptides is held in the sweet aspartyl tripeptide esters.In order for the