title: Efficient and Selective Chemical Labeling of Electrochemically Generated Peptides Based on Spirolactone Chemistry.
abstract: Specific digestion of proteins is an essential step for mass spectrometry-based proteomics, and the chemical labeling of the resulting peptides is often used for peptide enrichment or the introduction of desirable tags. Cleavage of the peptide bond following electrochemical oxidation of Tyr or Trp results in a spirolactone moiety at the newly formed C-terminus offering a handle for chemical labeling. In this work, we developed a highly efficient and selective chemical labeling approach based on spirolactone chemistry. Electrochemically generated peptide-spirolactones readily undergo an intramolecular rearrangement yielding isomeric diketopiperazines precluding further chemical labeling. A strategy was established to prevent intramolecular arrangement by acetylating the N-terminal amino group prior to electrochemical oxidation and cleavage allowing the complete and selective chemical labeling of the tripeptide LWL and the decapeptide ACTH 1-10 with amine-containing reagents. As examples, we show the successful introduction of a fluorescent label and biotin for detection or affinity enrichment. Electrochemical digestion of peptides and proteins followed by efficient chemical labeling constitutes a new, powerful tool in protein chemistry and protein analysis.
authors.affiliation: Analytical Biochemistry and Interfaculty Mass Spectrometry Center, Department of Pharmacy, University of Groningen , A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands.
authors.forename: Tao
authors.initials: T
authors.lastname: Zhang
authors.affiliation: Analytical Biochemistry and Interfaculty Mass Spectrometry Center, Department of Pharmacy, University of Groningen , A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands.
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Niu
authors.affiliation: Analytical Biochemistry and Interfaculty Mass Spectrometry Center, Department of Pharmacy, University of Groningen , A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands.
authors.forename: Tao
authors.initials: T
authors.lastname: Yuan
authors.affiliation: Institute for Molecules and Materials, Radboud University , Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands.
authors.forename: Marco
authors.initials: M
authors.lastname: Tessari
authors.affiliation: Department of Pediatrics, University Medical Center Groningen, University of Groningen , Hanzeplein 1, 9713 GZ, Groningen, The Netherlands.
authors.forename: Marcel P
authors.initials: MP
authors.lastname: de Vries
authors.affiliation: Analytical Biochemistry and Interfaculty Mass Spectrometry Center, Department of Pharmacy, University of Groningen , A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands.
authors.forename: Hjalmar P
authors.initials: HP
authors.lastname: Permentier
authors.affiliation: Analytical Biochemistry and Interfaculty Mass Spectrometry Center, Department of Pharmacy, University of Groningen , A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands.
authors.forename: Rainer
authors.initials: R
authors.lastname: Bischoff
mesh_terms: D000107:Acetylation; D000588:Amines / Q000737:chemistry; D001710:Biotin / Q000737:chemistry; D055664:Electrochemical Techniques / Q000379:methods; D005456:Fluorescent Dyes / Q000737:chemistry*; D010084:Oxidation-Reduction; D010455:Peptides / Q000737:chemistry*; D010879:Piperazines / Q000737:chemistry; D013148:Spironolactone / Q000737:chemistry*; D013194:Staining and Labeling / Q000379:methods
chemical_list: D000588:Amines; D005456:Fluorescent Dyes; D010455:Peptides; D010879:Piperazines; D013148:Spironolactone; D001710:Biotin