Skip to main content
. Author manuscript; available in PMC: 2013 Apr 11.
Published in final edited form as: J Am Chem Soc. 2012 Mar 28;134(14):6491–6497. doi: 10.1021/ja301491h

Table 3.

Reactivity of OND 1t with model peptidic nucleophiles

Nucleophile (pKa) kobs, M-1s-1a kNu, M-1s-1b krel (Nu)c
N-acetylcysteine (9.52)15 64.3 ± 5.1 8540 143000
H-GlyGlyGly-OH (8.06)19 10.7 ± 1.2 × 10-3 0.0596 1
6-aminocaproate (10.80)20 0.36 ± 0.03 × 10-3 0.918 15.4
N-benzoylhistidine (7.08)21 0.38 ± 0.04 × 10-3 0.00057 0.0095
a

observed second-order rate constant in 0.2 M sodium phosphate, pH 7.4, 25 °C.

b

Reactivity of the nucleophilic form of an amino acid: kNu = kobs•([NuH+]/[Nu]), where Nu is the deprotonated (active) form of the nucleophile, the concentration of which was calculated from its reported pKa.

c

Relative rate constants calculated from the preceding column.