Date of Defense


Date of Graduation



Biological Sciences

First Advisor

Todd Barkman

Second Advisor

Blair Szymczyna


Enzymes can have many different functions within an organism. One such common function is methylation. The SABATH family of enzymes perform methylation of various organic acids. Many of the members of this family of enzymes have become specialized in the acid they methylate. For example: salicylic acid methyl transferase (SAMT) will primarily methylate salicylic acid, and benzoic acid methyl transferase (BAMT) will primarily methylate benzoic acid. By comparing the sequence of these enzymes, it has been found that a conserved region consisting of the sequence SSYSLMWLS appears in some form across all the members of the SABATH family. The 6th position of this sequence can vary, in that, it can be an M, H, or a Q. Enzymes of the SABATH family that have an M in the 6th position are extremely likely to prefer salicylic acid as a substrate over other molecules, while enzymes that have an H in the 6th position are likely to prefer benzoic acid as a substrate to other molecules. SABATH family enzymes with a Q in the 6th position have not been studied intensely and it is unclear if they will act like enzymes with an M in the same position or more like enzymes with an H. This study investigated SABATH family members with a Q in the 6th position of the binding motif of the Theobroma and Ricinus lineages. It was found that a these enzymes preferred salicylic acid over benzoic acid. It was concluded that SABATH family enzymes that contain a Q or an M in the 6th position of the binding motif will both prefer salicylic acid.

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Honors Thesis-Restricted

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Available for download on Wednesday, June 06, 2018