Date of Award

Summer 1999

Document Type

Dissertation - Restricted

Degree Name

Doctor of Philosophy (PhD)



First Advisor

Ryan, Michael D.

Second Advisor

Feinberg, Benjamin A.

Third Advisor

Kincaid, James R.

Fourth Advisor

Steinmetz, Mark G.

Fifth Advisor

Wilkie, Charles A.


An improved current signal is required in studying enzymatic reactions associated with electrochemical electron transfer. One method of achieving this is by adsorbing the enzyme onto an electrode surface. The strategy involves the use of antibody-antigen binding and of covalently linking E. coli sulfite sulfite reductase hemoprotein (SiR-HP) to the antibody. From the cyclic voltammetric data, the rate of electron transfer from the glassy carbon electrode to SiR-HP is faster compared to the intramolecular electron transfer from the enzyme's reducible centers to the substrate, sulfite. In addition, it appears that relative to the cluster, the siroheme may deliver more electrons to sulfite. Spectroelectrochemical experiments on Rhodobacter sphaeroides 2.43 MalE--nitrite reductase reveals that this enzyme undergoes a chemically reversible and direct redox reaction on a modified gold electrode. The thin-layer cyclic voltammetric data indicates that the rate of reduction of the enzyme is faster than the rate of reoxidation. This implies that, kinetically, nitrite reductase prefers the reduced state.



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