Purification and characterization of PRMT4 and PRMT1

Protein Arginine Methyltransferases (PRMTs) are a group of eukaryotic enzymes that catalyze the S-adenosyl methionine (SAM) dependent methylation of arginine residues in a variety of different proteins including histones H2A, H3, and H4. PRMT catalyzed arginine methylation has emerged as an important post-translational modification of proteins that helps regulate numerous cellular processes. Characterization of these enzymes at the molecular level is medically significant because PRMT activity appears to be dysregulated in numerous diseases, including hormone dependent cancers and heart disease. This thesis describes the optimization of PRMT4 purification and determination of initial steady state kinetic parameters for the enzyme. Also, efforts to characterize the catalytic mechanism of PRMT1 involved a pH rate profile study, which can be used to identify catalytically important residues in the enzyme and substrate. Completion of this project aids in the overall goal of the lab to design, synthesize and develop PRMT selective inhibitors; these inhibitors may represent lead compounds for the treatment of diseases in which PRMTs are dysregulated. PRMT specific inhibitors could also be used to study the in vivo role of PRMTs, which is not completely understood.