A fast perturbation in proton concentration can be induced in aqueoussolution using a pulsed ultraviolet laser and suitable photolabile compounds which, upon photoexcitation, irreversibly release protons. The volumechange and the rate constant for the reaction of the photodetached protons with proton-accepting groups in solution can be monitored using time resolved photoacoustics. A typical proton concentration jump of 1 μM can be obtained with a 200-μJ laser pulse at 308 nm. Reaction dynamics from 20 ns to 5 μs can be easily followed. The methodology we establish represents a direct, time-resolved measurement of the reactionvolume in protontransfer processes and an extension to the nanosecond–microsecond range of traditional relaxation techniques, such as stopped-flow. We report example applications to reactions involving simple molecules and polypeptides.
An experimental methodology for measuring volume changes in proton transfer reactions in aqueous solutions / Viappiani, Cristiano; Abbruzzetti, Stefania; Small, J. R.; Libertini, L. J.; Small, E. W.. - In: BIOPHYSICAL CHEMISTRY. - ISSN 0301-4622. - 73:(1998), pp. 13-22. [10.1016/s0301-4622(98)00108-2]
An experimental methodology for measuring volume changes in proton transfer reactions in aqueous solutions
VIAPPIANI, Cristiano;ABBRUZZETTI, Stefania;
1998-01-01
Abstract
A fast perturbation in proton concentration can be induced in aqueoussolution using a pulsed ultraviolet laser and suitable photolabile compounds which, upon photoexcitation, irreversibly release protons. The volumechange and the rate constant for the reaction of the photodetached protons with proton-accepting groups in solution can be monitored using time resolved photoacoustics. A typical proton concentration jump of 1 μM can be obtained with a 200-μJ laser pulse at 308 nm. Reaction dynamics from 20 ns to 5 μs can be easily followed. The methodology we establish represents a direct, time-resolved measurement of the reactionvolume in protontransfer processes and an extension to the nanosecond–microsecond range of traditional relaxation techniques, such as stopped-flow. We report example applications to reactions involving simple molecules and polypeptides.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
