Abstract

A fundamental understanding of condensed phase chemical reaction dynamics can be obtained from the study of biomolecules, particularly heme and heme proteins. The complexity of these systems gives rise to a rich variety of phenomena, allowing many aspects of condensed matter reactions to be examined. The rate theories and puzzles of hemeprotein kinetics have recently been discussed by Frauenfelder and Wolynes [1]. In this work we discuss new experiments on ligand binding to protoheme (Fe:protoporphyrin-IX) in a glassy matrix. We have studied the rebinding of carbon monoxide over a wide range of time [5ps-10ms] and temperature [300K–70K]. The significance of our results are that (1) the influence of friction and nonadibaticity on a condensed phase reaction can be directly investigated, (2) the influence of an inhomogeneous glassy matrix (glycerol-water 75:25) on the reaction can be studied, and (3) meaningful comparison between protoheme and hemeprotein kinetics isolates the role of the protein relaxation in the reaction.

© 1986 Optical Society of America