Abstract

Vibrational lifetimes of CO bound to myoglobin and to a water-soluble Fe:porphyrin were measured by ps infrared experiments. Vibrational relaxation rates are found to depend on protein conformational substate and porphyrin substitution. We have made direct measurements of molecular energy transfer at the active site of a protein using intense tunable mid-IR pulses from a free-electron laser to measure the loss of vibrational energy from CO bound to a bare water soluble heme and CO bound to the active sites of different conformational substates of myoglobin. Vibrational relaxation rates are found to depend on protein conformational substate and porphyrin substitution.

© 1994 Optical Society of America