跳转至内容
Merck

Gas-phase tyrosine-to-cysteine radical migration in model systems.

European journal of mass spectrometry (Chichester, England) (2015-08-27)
Michael Lesslie, Sandra Osburn, Michael J van Stipdonk, Victor Ryzhov
摘要

Radical migration, both intramolecular and intermolecular, from the tyrosine phenoxyl radical Tyr(O(∙)) to the cysteine radical Cys(S(∙)) in model peptide systems was observed in the gas phase. Ion-molecule reactions (IMRs) between the radical cation of homotyrosine and propyl thiol resulted in a fast hydrogen atom transfer. In addition, radical cations of the peptide LysTyrCys were formed via two different methods, affording regiospecific production of Tyr(O(∙)) or Cys(S(∙)) radicals. Collision-induced dissociation of these isomeric species displayed evidence of radical migration from the oxygen to sulfur, but not for the reverse process. This was supported by theoretical calculations, which showed the Cys(S(∙)) radical slightly lower in energy than the Tyr(O(∙)) isomer. IMRs of the LysTyrCys radical cation with allyl iodide further confirmed these findings. A mechanism for radical migration involving a proton shuttle by the C-terminal carboxylic group is proposed.

材料
货号
品牌
产品描述

Sigma-Aldrich
甲醇, ACS reagent, ≥99.8%
Sigma-Aldrich
乙腈, anhydrous, 99.8%
Sigma-Aldrich
乙腈, ACS reagent, ≥99.5%
Sigma-Aldrich
甲醇, puriss. p.a., ACS reagent, reag. ISO, reag. Ph. Eur., ≥99.8% (GC)
Sigma-Aldrich
甲醇, Laboratory Reagent, ≥99.6%
Sigma-Aldrich
甲醇, anhydrous, 99.8%
Sigma-Aldrich
甲醇, BioReagent, ≥99.93%
Sigma-Aldrich
甲醇, Absolute - Acetone free
Sigma-Aldrich
甲醇, ACS spectrophotometric grade, ≥99.9%
Sigma-Aldrich
亚硝酸叔丁酯, 90%
Sigma-Aldrich
甲醇, ACS reagent, ≥99.8%
Sigma-Aldrich
甲醇, JIS special grade, ≥99.8%
Sigma-Aldrich
乙腈, biotech. grade, ≥99.93%
Sigma-Aldrich
乙腈, HPLC Plus, ≥99.9%, poly-coated bottles
Sigma-Aldrich
甲醇, SAJ first grade, ≥99.5%
Sigma-Aldrich
甲醇, ACS reagent, ≥99.8%
Sigma-Aldrich
乙腈 溶液, contains 0.1 % (v/v) trifluoroacetic acid, suitable for HPLC
Sigma-Aldrich
乙腈, ReagentPlus®, 99%
Sigma-Aldrich
乙腈 溶液, contains 0.1 % (v/v) formic acid, suitable for HPLC
Sigma-Aldrich
1-丙硫醇, 99%
Sigma-Aldrich
甲醇, puriss., meets analytical specification of Ph Eur, ≥99.7% (GC)
Sigma-Aldrich
乙腈, electronic grade, 99.999% trace metals basis
Sigma-Aldrich
乙腈, suitable for DNA synthesis, ≥99.9% (GC)
Sigma-Aldrich
烯丙基碘, 98%
Sigma-Aldrich
甲醇, suitable for HPLC
Supelco
乙腈, HPLC grade, ≥99.93%
Sigma-Aldrich
甲醇, SAJ special grade
Sigma-Aldrich
乙腈, ≥99.8%, suitable for HPLC
Sigma-Aldrich
丙基硫醇, ≥97%
Sigma-Aldrich
甲醇, suitable for HPLC, gradient grade, 99.93%