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. Author manuscript; available in PMC: 2014 Aug 19.
Published in final edited form as: Mass Spectrom Rev. 2014 May-Jun;33(3):157–182. doi: 10.1002/mas.21389

Table 8.

Calculated at the ub3lyp/6-311+g(d,p) level of theory the nucleophilicity indexes, ω−, of cysteine and model Ala-Cys-Ala tripeptide in their reactions with electrophilic derivatives of cyclopentenone in different ionization states (indicated in round brackets). The nucleophilicity indexes of nonconjugated epoxide are shown for comparison.

Electrophile ω− (eV)
Cys
(−1)		 Cys
(0)		 Ala-Cys-Ala
(−1)		 Ala-Cys-Ala
(0)
15d-PGJ2 1.872 0.0077 1.374 0.02
Δ12-PGJ2 1.547 0.00398 1.113 0.013
PGA2 1.496 0.00486 1.074 0.014
PGJ2 1.491 0.00101 1.065 0.007
Cyclopentene 1.399 0.00294 0.996 0.011
Epoxide 0.657 0.00352 0.432 0.0004