The potential to measure the internal dynamics of a membrane protein, the bacterial photochemical reaction center (RC) from the photosynthetic bacterium Rhodobacter sphaeroides, was investigated by incoherent quasi-elastic neutron scattering (IQENS) and neutron spin-echo spectroscopy. To isolate and maximize the scattering intensity attributed to the protein, selective deuteration was employed. This deuteration was achieved by embedding detergent-purified RC proteins in a solution containing perdeuterated D-28-n-octyl-beta-D-glucopyranoside, a sugar-hydroxy detergent. Therefore, the IQENS signal essentially arises only from the motions, which are resolved in time, of the nonexchangeable hydrogen atoms of the protein. This work has established that with a suitable biochemical protocol detailed measurements on the internal dynamics of any integral membrane protein can be undertaken.