ISSN:
0749-1581
Keywords:
1H NMR
;
Metmyoglobin
;
Fluorometmyoglobin
;
Horse heart
;
Sperm whale
;
Proton relaxometry
;
Field cycling NMR
;
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The measurement of longitudinal relaxation rates of water protons in solutions containing horse heart and sperm whale metmyoglobins at various pH values and temperatures shows that the two species differ essentially in the exchange lifetime, τM, of the water molecule in the haem cavity. The 1/T1 nuclear magnetic relaxation dispersion dispersion profiles support this view whereas 17O NMR spectroscopy shows that the exchange mechanism involves the whole water molecule. The lack of any 1H/2H isotope effect on the exchange rate suggests that the displacement of the coordinated water molecule from Fe(III) is not the rate-determining step in the overall exchange process. In contrast to the parent species, no difference is detectable from the relaxometric investigations on the corresponding fluorometmyoglobin derivatives.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrc.1260311317
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