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|Title:||Selective bi-directional amide bond cleavage of N-methylcysteinyl peptide||Authors:||Qiu, Yibo
Liu, Ding Xiang
Tam, James P.
|Keywords:||DRNTU::Science::Chemistry::Organic chemistry||Issue Date:||2014||Source:||Qiu, Y., Hemu, X., Liu, D. X., & Tam, J. P. (2014). Selective Bi-directional Amide Bond Cleavage of N-Methylcysteinyl Peptide. European Journal of Organic Chemistry, 2014(20), 4370-4380.||Series/Report no.:||European journal of organic chemistry||Abstract:||A selective bi-directional peptide bond cleavage mediated by N-methylcysteine (MeCys) in Xaa-MeCys-Yaa peptides (Xaa and Yaa, non-cysteine residues) leading to thioesters and thiolactones is described. Rate and product analyses showed that an Nα-amide bond cleavage occurred at the Xaa-MeCys bond by an N–S acyl shift to generate an Xaa-S-(MeCys-Yaa) thioester at pH 1–5, whereas under strongly acidic conditions of H0 = –5, the MeCys-Yaa bond underwent a Cα-amide bond cleavage via an oxazolone intermediate, which was trapped by thiocresol (TC) as an Xaa-MeCys-TC thioester. This thioester was then transformed into an Xaa-MeCys-β-thiolactone at pH 4–5. Replacing MeCys by a Cys residue did not result in significant bi-directional peptide bond cleavage, which suggests that N-methylation in a MeCys residue is important for the N–S acyl shift reaction and formation of oxazolone. The isomerization of amides and thioesters was successfully used to prepare cyclic peptides.||URI:||https://hdl.handle.net/10356/103981
|ISSN:||1434-193X||DOI:||http://dx.doi.org/10.1002/ejoc.201402261||Rights:||© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.||Fulltext Permission:||none||Fulltext Availability:||No Fulltext|
|Appears in Collections:||SBS Journal Articles|
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