Incorporation of two18O atoms into a peptide during isoaspartyl repair reveals repeated passage through a succinimide intermediate |
| |
Authors: | Jonathan A. Lindquist and Philip N. McFadden |
| |
Affiliation: | (1) Department of Biochemistry and Biophysics, Oregon State University, 97331 Corvallis, Oregon |
| |
Abstract: | To study the mechanism of protein carboxyl methyltransferase-driven repair of age-damaged sites in polypeptides, a modell-isoaspartyl peptide,l-isotetragastrin, was enzymatically repaired to normall-tetragastrin in the presence of18O-enriched water. By this design, the enrichment of18O atoms in the peptide would reflect the number of passages through a hydrolyzable succinimide intermediate during formation of the repaired product. Mass determinations by FAB mass spectrometry revealed repaired peptide with two18O atoms incorporated, demonstrating that more than a single cycle of methylation and demethylation is necessary to ensure stoichiometric repair.Abbreviations HPLC high-pressure liquid chromatography - FAB fast atom bombardment - TFA trifluoroacetic acid - PCM proteind-aspartyl/L-isoaspartyl carboxyl methyltransfer-ase - l-Normal [l-Asp3]tetragastrin - l-Iso [L-isoAsp3]tetragastrin - d-Normal [d-Asp3]tetragastrin - d-Iso [d-isoAsp3]tetragastrin |
| |
Keywords: | Protein font-variant:small-caps" >d-aspartyl/ font-variant:small-caps" >l-isoaspartyl carboxyl methyltransferase protein repair HPLC aging fast-atom bombardment mass spectrometry |
本文献已被 SpringerLink 等数据库收录! |