51776-33-1Relevant academic research and scientific papers
Hydrolytic cleavage of pyroglutamyl-peptide Bond. V. Selective removal of pyroglutamic acid from biologically active pyroglutamylpeptides in high concentrations of aqueous methanesulfonic acid
Kobayashi, Junko,Ohki, Kazuhiro,Okimura, Keiko,Hashimoto, Tadashi,Sakura, Naoki
, p. 827 - 831 (2007/10/03)
Application of aqueous methanesulfonic acid (MSA) for selective chemical removal of pyroglutamic acid (pGlu) residue from five biologically active pyroglutamyl-peptides (pGlu-X-peptides, X=amino acid residue at position 2) was examined. Gonadotropin releasing hormone (Gn-RH), dog neuromedin U-8 (d-NMU-8), physalaemin (PH), a bradykinin potentiating peptide (BPP-5a) and neurotensin (NT) as pGlu-X-peptides were incubated in either 70% or 90% aqueous MSA at 25°C. HPLC analysis of the incubation solutions showed that the main decomposition product was H-X-peptide derived from each pGlu-X-peptide by the removal of pGlu. The results revealed that the pGlu-X peptide bond had higher susceptibility than various internal amide bonds in the five peptides examined, including the Trp-Ser bond in Gn-RH, the C-terminal Asn-NH2 in d-NMU-8, and the Asp-Pro bond in PH, whose acid susceptibility is well known. Thus, mild hydrolysis with high concentrations of aqueous MSA may be applicable to chemically selective removal of pGlu from pGlu-X-peptides for structural examinations.
Degradation kinetics of gonadorelin in aqueous solution
Hoitink, Marnix A.,Beijnen, Jos H.,Bult, Auke,Van Der Houwen, Oeds A. G. J.,Nijholt, Jack,Underberg, Willy J. M.
, p. 1053 - 1059 (2007/10/03)
The degradation kinetics of gonadorelin were investigated systematically with reversed-phase high-performance liquid chromatography. The stability- indicating properties of this system were checked with photodiode array detection and by comparison with capillary zone electrophoretic analysis. Influences of gonadorelin concentration, pH, temperature, buffer ions, and ionic strength on the degradation kinetics were studied. The pH-Iog κ(abs) profile can be divided into three pads, a proton, a solvent, and a hydroxyl- catalyzed section, with different degradation products. These degradation products were characterized by mass using LC-MS. Gonadorelin is most stable at pH 5-5.5 with a half-life of 70 days at 70 °C. The overall degradation rate constant as a function of the temperature under acidic and alkaline conditions obeys the Arrhenius equation. The gonadorelin concentration and the concentrations of acetate, phosphate, borate, and carbonate buffer have no influence on the decomposition rate of the κ(abs). Increasing ionic strength led to higher κ(abs) at pH 2 and lower κ(abs) at pH 9, but influences were relatively small.
