Scheme 3. (a) Thiazolidine formation and stability at various pH values. (b) Left – UV-vis absorption of 2-FBBA and the reaction mixture at 5 min; right – kobs values plotted against the concentration of cysteine to yield the second order rate constant (k2, M–1 s–1) from the slope of the line. (c) Probes for the modification of cysteine.
