Second order rate constants, k_AcO⁻, k_DO, and k_HO, of the TKPs studied with 40% d₃-MeCN co-solvent at 25 °C and I = 0.06–0.20 M (KCl).

	k AcO− a (M−1 s−1)	k DO (M−1 s−1)	k HO b (M−1 s−1)
Gly TKP	7.21 × 10−2	5.09 × 105	6.40 × 104
Pro TKP	1.61 × 10−2	8.99 × 106	1.14 × 106

^a k _AcO⁻ is the second order rate constant for deprotonation by acetate anion and was obtained as the slope of k^obs_exversus buffer concentration plots at pD 6.28 for Gly TKP and pD 4.76–5.28 for Pro TKP.

^bA secondary solvent isotope effect of k_DO/k_HO = 1.46 was used to convert k_DO to k_HO.