ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
Ultrafast spectroscopy is used to investigate the temperature dependence of a bimolecular chemical reaction occurring at reaction centers embedded in a glycerol:water glass. The reaction centers consist of carbon monoxide bound to protoheme (PH–CO), or to myoglobin at pH=3 (Mb3–CO), a protein containing PH–CO with a broken proximal histidine–Fe bond. These systems have in common a small energetic barrier for rebinding of the photodissociated ligand. In the glass, the ligand is caged, so that only geminate rebinding is possible. Rebinding is not exponential in time. For t(approximately-greater-than)20 ps, the survival fraction of deligated heme N(t)∝t−n(n≥0). Below 100 K, rebinding is dominated by an inhomogeneous distribution of activation enthalpy P(ΔH
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.459957
Permalink