- Hydrolytic cleavage of pyroglutamyl-peptide Bond. V. Selective removal of pyroglutamic acid from biologically active pyroglutamylpeptides in high concentrations of aqueous methanesulfonic acid
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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.
- Kobayashi, Junko,Ohki, Kazuhiro,Okimura, Keiko,Hashimoto, Tadashi,Sakura, Naoki
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p. 827 - 831
(2007/10/03)
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- Characterization of the degradation products of luteinizing hormone releasing hormone
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The degradation products of luteinizing hormone releasing hormone [LH/RH; 1; gonadorelin releasing hormone (GnRH); 2] were determined in aqueous solution (pH 6.5) at 25, 37, 50, and 80 °C. The predominant route of degradation involved the cleavage of the 2 to the free acid form in peptides 4 and 10. Racemization of the serine and histidine residues to give peptides 2 and 3 was a second route of degradation.
- Motto,Hamburg,Graden,Shaw,Cotter
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p. 419 - 423
(2007/10/02)
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- PREPARATION AND APPLICATION OF NEW ACID LABILE ANCHOR GROUPS FOR THE SYNTHESIS OF PEPTIDE AMIDES BY FMOC SOLID PHASE SYNTHESIS
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The synthesis and application of new linkage agents for the preparation of peptide amides using a modified Fmoc strategy is described.
- Breipohl, G.,Knolle, J.,Stueber, W.
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p. 5651 - 5654
(2007/10/02)
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- Synthetic decapeptide having the activity of the luteinizing hormone releasing hormone and method for producing the same
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A synthetic decapeptide, L-pglutamyl-L-histidyl-L-tryptophanyl-L-seryl-L-tyrosyl-glycyl-L-leucyl-L-arginyl-L-prolyl-glycinamide having the hormonal activity of the luteinizing hormone releasing hormone (LRH) of the hypothalamus gland of mammals is provided by utilizing, as key starting materials, the amino acids, pyroglutamic acid, histidine, tryptophan, serine, tyrosine, glycine, leucine, arginine, proline. Synthesis of the decapeptide is accomplished by coupling, in appropriate protected forms, all of the remaining amino acids, individually or in combination, to the starting amino acid, or amino acid group or to the terminal amino acid resulting from combinations with one or more other amino acids, bound to a resin or carrier followed by release of the decapeptide from the carrier as the amide or other form which is converted to the amide, L-pglutamyl-L-histidyl-L-tryptophanyl-L-seryl-L-tyrosyl-glycyl-L-leucyl-L-arginyl-L-prolyl-glycinamide.
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