Detection of a Quinone Intermediate in the Biogenesis Pathway of Lysyl Tyrosylquinone Cofactor
Mentor:Karlo Lopez, Assistant Professor of Chemistry, California State University Bakersfield
Lysyl oxidase (LOX) is a copper-dependent enzyme that activates the formation of cross linkages of collagen and elastin in connective tissues by oxidative deamination of lysine. Aside from copper, the enzyme also contains the carbonyl cofactor lysyl tyrosylquinone (LTQ) that enables this enzyme to efficiently catalyze cross linkages of connective tissues. Studies show that LOX has many practical functions in biological systems including, tumor suppression, cell growth control, and developmental regulation. Changes in LOX mechanistic behavior help with understanding disorders such as fibrosis and joint problems. The K320R LOX mutant was made in the laboratory and has been successfully overexpressed in a heterologous expression system. This mutant is being studied in order to isolate and identify a key intermediate in the biogenesis of LTQ. The total protein yield obtained for this study was 13 mg of LOX per liter of media. SDS PAGE detected the LOX protein with a band at 29kDa. Following UV spectroscopy analysis, a phenylhydrazine adduct was observed at a wavelength of 430 nm, which confirms that a quinone intermediate was detected in the K320R LOX mutant. Further research needs to be performed in order to identify the type of quinone intermediate present in the K320R LOX mutant.