2020-2021 Grant in Aid of Research

The Function of Carboxypeptidase O (CPO) Duplicates in Xenopus Tropicalis

Ritchie Saint Jean

Carboxypeptidases are enzymes that remove amino acids from the C-termini of polypeptides through hydrolysis. Carboxypeptidase O (CPO) is one of these enzymes that cleaves acidic amino acids. This protease has been found in various invertebrates, vertebrates, and mammalian organisms. It has been hypothesized that the functions of CPO include intestinal digestion, folate processing, or the absorption of lipids. A search of a genome database has found CPO genes to be duplicated in several organisms. Gene duplication can lead to a duplicate gene becoming active or inactive. Unpublished work by Daniel Fajardo in the lab of P. Lyons at Andrews University has found four copies of CPO in Xenopus tropicalis. Here I propose to find out the function of the CPO duplicates in X. tropicalis. First I plan to transfect HEK293T cells and use western blotting to determine if the CPO genes have protein expression. Next, I will determine the subcellular localization of these proteins by the biological technique of immunocytochemistry. Lastly, I will use chromogenic substrates and luciferase assay to find the enzymatic function of the CPO duplicates. Ultimately, the information regarding these genes will help me to gain information about the functions of new enzymes following duplication events.