Table of Contents
Laser Chemistry
Volume 5, Issue 4, Pages 173-183

Quantum Yield of Thirty Picosecond Oxyhemoglobin Photodissociation. Effect of Protein Fluctuations on the Quantum Yield Values

1Institut Curie and Universite Paris VII, Centre Universitaire, Orsay 91405, France
2Institut Curie and Universit Paris VII, Place Jussieu, Paris 75251, France

Received 2 October 1984

Copyright © 1985 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


We have measured the absolute quantum yield of the oxyhemoglobin photodissociation with a 30 ps laser pulse excitation. We report that oxyhemoglobin dissociates with the same yield as carboxymyoglobin under photostationary conditions. Based on the picosecond and nanosecond experimental data, we show that oxygen geminate recombination is responsible for the low quantum yield values of oxyhemoglobin photodissociation measured with longer photolysis flashes. Kinetic data suggest that two geminate regimes which successively appear in oxygen recombination can be resolved. The first can be entirely attributed to the hemoglobin-iron chemical reactivity and, the second to the action of protein fluctuations.