Expression and mechanistic studies on orotidine-5'-monophosphate decarboxylase /

Abstract

Orotidine-5'-monophosphate decarboxylase, ODCase, catalyzes the conversion of OMP to UMP in the pyrimidine biosynthetic pathway. This enzyme is remarkable in both its rate enhancement and lack of a cofactor. For this reason, the mechanism has been under investigation. Currently, a new hypothesis raises the question as to whether the substrate binds with its C6 group or 02 group facing the lysine residue at position 93. To determine this, an isoteric inhibitor along with chemically modified and mutated ODCase clones would provide evidence through 15N labeled NMR samples. This thesis produced the resources necessary to chemically modify the protein by providing an adequate expression system and growth conditions for ODCase WT, CysFree, C930nly, and K93C.