Benzyloxycarbonyl-L-alanine p-guanidinophenyl ester behaves as a trypsin "inverse substrate," i.e., a cationic center is included in the leaving group instead of being in the acyl moiety. Using this substrate as an acyl donor, trypsin catalyzes the synthesis of peptide bonds that cannot be split by this enzyme. An optimal acyl transfer efficiency was achieved between pH 8 and 9 at 30 degrees C.The addition of as much as 50% cosolvent was shown to be of minor influence on the acyl transfer efficiency, whereas the reaction velocity decreases by more than one order of magnitude. The efficiency of H-Leu-NH(2) and H-Val-NH(2) in deacylation is almost the same for "inverse" and normal type substrates.
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http://dx.doi.org/10.1002/bit.260380114 | DOI Listing |
J Am Chem Soc
January 2025
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China.
While synthesizing circular polymers with telechelic polyolefin building blocks recently emerged as a promising strategy for addressing conventional polyethylenes' sustainability challenges, the lack of telechelic PP (PP) with sufficient difunctional purity for polycondensation has been limiting the development of circular polypropylenes with PP-like structures and properties. Here we described a combined approach of coordinative chain transfer polymerization and transition-metal-catalyzed quenching reaction with various acyl chlorides, affording PPs with a high difunctional ratio (up to ∼99%) and broad end functional group scope. The steric effect of polymeryl-Zn species and the role of Pd catalyst were revealed by DFT.
View Article and Find Full Text PDFOrg Biomol Chem
January 2025
School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, 3010, Victoria, Australia.
Despite advances in solid phase peptide synthesis and peptide ligation, challenges remain in the assembly of polypeptides through coupling of peptide fragments. Herein we describe a new method for peptide fragment coupling employing the Ag(I)-promoted transformation of peptide thioamides. This process proceeds an isoimide-tethered intermediate, which undergoes an O-N acyl transfer to generate the polypeptide.
View Article and Find Full Text PDFCell Death Discov
January 2025
Department of Gynaecology and Obstetrics, Xijing Hospital, Air Force Medical University, Xi'an, China.
Mitochondrial dysfunctions are closely associated with different types of disease, including cancer. Carnitine acetyltransferase (CRAT) is a mitochondrial-localized enzyme catalyzing the reversible transfer of acyl groups from an acyl-CoA thioester to carnitine and regulates the ratio of acyl-CoA/CoA. Our bioinformatics analysis using public database revealed a significant decrease of CRAT expression in ovarian cancer (OC).
View Article and Find Full Text PDFJ Org Chem
January 2025
College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, People's Republic of China.
We herein disclose a visible-light-induced synthesis of aryl esters through the cross-dehydrogenative coupling of aldehydes with phenols using BrCCl, in which phenolate functions as both a substrate and a photosensitizer. This transition-metal- and photocatalyst-free visible-light-induced esterification is suitable for a wide range of substrates and gives moderate to excellent yields (up to 95%). Mechanistic studies provided evidence of a self-propagating radical reaction involving homolytic cleavage of the aldehydic C-H bond and the formation of acyl bromides.
View Article and Find Full Text PDFAnal Chem
January 2025
Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States.
Lipid A, a well-known saccharolipid, acts as the inner lipid-glycan anchor of lipopolysaccharides in Gram-negative bacterial cell membranes and functions as an endotoxin. Its structure is composed of two glucosamines with β(1 → 6) linkages and various fatty acyl and phosphate groups. The lipid A structure can be used for the identification of bacterial species, but its complexity poses significant structural characterization challenges.
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