The gene encoding for cytochrome c-551, nirM, in Pseudomonas stutzeri ZoBell was altered through the use of site-directed mutagenesis. There is a poly-proline region in cytochrome c-551, spanning from residue 58-65. Proline appears at residue 58, 60, 62, and 63. The residues at positions 62-63 are descriptive of a di-proline turn in the protein structure. The residue altered for this research proposal is the 62nd residue of cytochrome c-551. This residue was converted from a proline to a lysine residue through site-directed mutagenesis and the use of oligonucleotides to produce the desired sequences of the nirM gene. This gene was then ligated into expression vectors, which were transformed into Escherichia coli. Since the sixth ligand to the heme is positioned at the 61st residue (methionine), the use of visible spectroscopy research can determine whether the methionine is still ligated to the heme due to conformational changes in protein folding. Also, lysine introduces a positive residue within the heme crevice. This charge is important to eukaryotic type cytochrome c, and their interaction with cytochrome oxidases. The electron transport potential between the Pro62Lys mutant and the bacterial or mitochondrial oxidase complexes can be measured. The thermal stability, which is determined by temperature, of the wild-type c-551 versus the mutant variation was monitored by the Soret band absorbance. The stability of wild-type c-551 and the mutant will be monitored by the Soret band absorbance versus increasing concentrations of guanidine hydrochloride (C-H bond disruptor).