Protein kinase domains transfer the γ phosphate of an ATP molecule to a serine, threonine, or tyrosine residue of a protein or peptide substrate1. This phosphorylation can activate or deactivate the protein, meaning that kinases are often important regulators of various cell activities. The active sites of kinase domains are highly conserved as they all bind ATP and have similar functions1. Kinases are very popular drug targets as they play a significant role in cell signaling pathways. Kinase dysregulation has been shown to play a role in many cancers and other diseases, making them a popular target for drugs4. Identifying key differences between different kinase domains could help design highly specific drugs, which would minimize the more severe side effects often seen in other, less specific drugs. MAPK14, an important mitogen activated protein kinase, is involved in the regulation of the cell cycle in response to environmental stress and proinflammatory cytokines2. It is a serine-threonine kinase that has been found to regulate the cell cycle at G0, G1/S, and G2/M transition stages. It can differentially monitor cyclin levels, as well as phosphorylate a number of different tumor suppressor proteins2. MAPK14 can also be activated during normal cellular proliferation and differentiation, as it is a key regulator of hematopoiesis and other important processes3. Experiments performed in CHEM 406 lab failed to determine the melting temperature of MAPK14, as it never melted during the experiments performed. To understand why this may have occurred, circular dichroism (CD) experiments were performed using the standard phosphate buffer, as well as varying concentrations of GuHCl in conjunction with the phosphate buffer. The His tag was also removed, and circular dichroism experiments were performed again, also with almost no success. It is likely that the protein is melting, as a difference in the CD spectra can be seen as the temperature was increased slowly. However, it is likely that the initial experiments failed because the temperature increased too rapidly and melting of the protein could not be detected.