HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Saffran, W. A. Articles by Gibson, Q. H. Search for Related Content PubMed PubMed Citation Articles by Saffran, W. A. Articles by Gibson, Q. H. Social Bookmarking                      What's this?

JBC, Vol. 252, Issue 22, 7955-7958, Nov, 1977

Photodissociation of ligands from heme and heme proteins. Effect of temperature and organic phosphate

W. A. Saffran and Q. H. Gibson

The effect of temperature on ligand photodissociation from protoheme and the heme proteins hemoglobin (Hb) and myoglobin (Mb) has been examined. The quantum yield of photodissociation (phi) is greater at 40 degrees than at 0 degrees; in general, larger increases are seen in the less photosensitive complexes, while phi does not change in the most photosensitive complexes. The ratio of phi at 40 degrees to phi at 0 degrees is 1.8 for HbCO, 2.3 for n-butyl isocyanide Hb, 2.7 for HbO2, and 1.3 for HbNO, with initial phi values of 0.38, 0.26, 0.028, and 0.003, respectively. This pattern of quantum yield increases is seen in protoheme as well as Hb and Mb ligand photolysis. The allosteric effector inositol hexaphosphate increases the quantum yield of lignad photolysis from hemoglobin. As with temperature, inositol hexaphosphate addition has a larger effect on complexes of low quantum yield; phi increases 1.2-fold for HbCO and 2.2-fold for HbO2 at 0 degrees. The results are discussed in terms of a model containing a photoexcited intermediate (Phillipson, P.E., Ackerson, B.J., and Wyman, J. (1973) Proc. Natl. Acad. Sci. U.S.A. 70, 1550-1553).
CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				R. J. Rohlfs, E. Bruner, A. Chiu, A. Gonzales, M. L. Gonzales, D. Magde, M. D. Magde Jr., K. D. Vandegriff, and R. M. Winslow Arterial Blood Pressure Responses to Cell-free Hemoglobin Solutions and the Reaction with Nitric Oxide J. Biol. Chem., May 15, 1998; 273(20): 12128 - 12134. [Abstract] [Full Text] [PDF]