54300-25-3Relevant academic research and scientific papers
Thermodynamic and (1)H NMR Study of Proton Complex Formation of Histidine-containing Cyclodipeptides in Aqueous Solution
Arena, Giuseppe,Impellizzeri, Giuseppe,Maccarrone, Giuseppe,Pappalardo, Giuseppe,Sciotto, Domenico,Rizzarelli, Enrico
, p. 371 - 376 (2007/10/02)
A thermodynamic and (1)H NMR study of proton complex formation in aqueous solution of some L-histidine-containing cyclic L-dipeptides has been carried out.The enthalpic and entropic changes associated with protonation of the cyclodipeptides, obtained by potentiometric and calorimetric measurements, together with the (1)H NMR data and NOESY experiments, enable the role played by non-covalent interactions in proton complex formation to be assessed.In addition, a comparison with c(Gly-His) permits the influence of side-chain residues on the conformation of protonated species to be observed.
Hydrolysis of Active Esters of Aliphatic Carboxylic Acids with Cyclic Dipeptide Catalysts Consisting of L-Histidine and Different Aliphatic α-Amino Acids
Masuda, Yoshihiko,Tanihara, Masao,Imanishi, Yukio,Higashimura, Toshinobu
, p. 497 - 504 (2007/10/02)
The hydrolyses of a series of p-nitrophenyl carboxylates with different acyl chains were investigated at 25 deg C, pH 7.8 using cyclic dipeptides as catalyst.Consequently, cyclo(-D-Leu-L-His) and cyclo(-D-Val-L-His-) were found to be specifically effective catalyst for the hydrolysis of p-nitrophenyl laurate.These trans (D-L-type) cyclic dipeptides were much more efficient catalysts than their diastereoisomers, and were more reactive than imidazole, despite the fact that the former are less basic than latter.The conformation of the cyclic peptides in solution was investigated using proton magnetic spectroscopy and the relationship between conformation and catalytic activity was investigated.Consequently, it was found that the hydrophobic interaction between a catalyst and a substrate and the stereochemical fit for the cooperation of functional groups in the intramolecular nucleophilic catalysis are very important in order to attain a highly efficient catalysis.It was also found that the functional groups should have a certain size and flexibility in order to realize an effective stereochemical fit between functional groups of catalysts and substrates.
