To study the correlation between internal protein dynamics and protein functionality of bacteriorhodopsin, we have performed time-resolved quasielastic neutron scattering (QENS) experiments combined with in situ laser activation of protein function. A set of purple membrane samples with different lamellar lattice constants and, hence, different hydration levels has been examined at different time delays between the laser and neutron pulses. While the water content affected the lineshapes of QENS spectra, the laser-induced response remained constant within the accuracy of the method.