Date of Award

Fall 1997

Project Type


Program or Major


Degree Name

Doctor of Philosophy

First Advisor

N Dennis Chasteen


An X-band Electron Nuclear Double Resonance (ENDOR) spectrometer was constructed, tested at both room and liquid helium temperatures, and characterized at liquid helium temperature using a vanadyl-imidazole standard.

An iron nitrosyl complex of transferrin was studied. Three methods of generating nitric oxide gas were tested and resulted in no differences in product formation. The g-factors for the rhombic complex--prepared with and without carbonate addition to the buffer--were determined. For the complex prepared with carbonate g$\sb{\rm x}$ = 2.052, g$\sb{\rm y}$ = 2.028, and g$\sb{\rm z}$ = 2.013. For the complex prepared without addition of carbonate g$\sb{\rm x}$ = 2.051, g$\sb{\rm y}$ = 2.028, and g$\sb{\rm z}$ = 2.011. Complex concentration was little affected by the addition of extra Fe$\sp{2+},$ but does decrease over time after reaching a maximum two to three minutes after the start of the reaction. The complex was observed to form preferentially at the C-terminal lobe of the protein. The histidine residue, which normally serves as a ligand for Fe$\sp{+3}$ does not appear to be necessary for binding of the iron nitrosyl complex. An ENDOR spectrum of the complex obtained at 3.6 K yielded a signal attributed to the effect of matrix protons.