1487
J . A m . Chem. SOC.1992, 114, 1487-1488
Acknowledgment. We are grateful for financial support for this work from the Office of the Naval Research (Grant No. N00014-87-0256). S.A.L. is supported by a Helen Hay Whitney Fellowship, B.G. is supported by a Damon Runyon-Walter Winchell Cancer Research Fund Fellowship, DRG-1138, and P.G.S. is a W. M. Keck Foundation Investigator.
llls
500ns
Ligand Photodissociation and Recombination Dynamics of Ferrous Cytochrome c Peroxidase at Alkaline pH
25011s
Jianling Wang,+ Randy W. Larsen,* Sunney I. Chan,*sr Nancy J. Boldt,+ and Mark R. Ondrias*xt
50ns
Department of Chemistry, University of New Mexico Albuquerque, New Mexico 871 31 Arthur Amos Noyes Laboratory of Chemical Physics California Institute of Technology Pasadena, California 91 125 Received October 18, 1991 The dynamics associated with ligand photodissociation and ligand binding provide an avenue through which information concerning conformational interactions involving the active site of heme proteins may be obtained. To date, most time-resolved spectroscopic investigations have involved exogenous n-acceptor ligands such as CO, 02,and In fact, until very recently hexamrdinate low-spin hemes with strong-field a-donor ligands were considered to be largely nonphotolabile. Magda and coworkers4have, however, demonstrated that both cytochrome c and cytochrome b5 exhibit photodissociation of nitrogenous ligands on a very fast (
