Determination of Optimal Assay Conditions for a Lethal ITPA Mutant
Faculty Mentor
Nicholas Burgis
Presentation Type
Poster
Start Date
May 2025
End Date
May 2025
Location
PUB NCR
Primary Discipline of Presentation
Chemistry and Biochemistry
Abstract
Inosine triphosphate pyrophosphatase (ITPA) is an important enzyme in humans that breaks down inosine triphosphate (ITP) nucleotides into inosine monophosphate (IMP) and pyrophosphate, preventing excess amounts of ITP from forming. However, some ITPA mutants are unable to function properly, leading to various medical conditions and diseases caused by increased levels of ITP. One severe mutant, labeled R178C, modifies an arginine residue into cysteine at the 178th amino acid position. The R178C protein has reduced stability, but is able to bind to the substrate. However, it catalyzes the reaction at a much slower rate. This then leads to a fatal encephalopathy in newborns. It is imperative that R178C be studied to help create treatment options for this condition. To better study the R178C protein, magnesium chloride and pH assays of the protein were performed alongside wild type ITPA. The data was measured using high performance liquid chromatography. Assays showed that significant levels of magnesium are necessary for the function of both R178C and wild type ITPA. The pH optima of wild type ITPA was found to be 8.5 while R178C had the highest activity at a lower pH. This information will be used to make a standardized procedure for the development of a chemical screening assay for the discovery of molecules that stabilize R178C.
Recommended Citation
Burgis NE, April C, VanWormer K. Arginine-178 is an essential residue for ITPA function. Arch Biochem Biophys. 2023 Aug;744:109700. doi: 10.1016/j.abb.2023.109700. Epub 2023 Jul 26. PMID: 37506994; PMCID: PMC10530447. Burgis NE. A disease spectrum for ITPA variation: advances in biochemical and clinical research. J Biomed Sci. 2016 Oct 22;23(1):73. doi: 10.1186/s12929-016-0291-y. PMID: 27770805; PMCID: PMC5075207.
Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-No Derivative Works 4.0 International License.
Determination of Optimal Assay Conditions for a Lethal ITPA Mutant
PUB NCR
Inosine triphosphate pyrophosphatase (ITPA) is an important enzyme in humans that breaks down inosine triphosphate (ITP) nucleotides into inosine monophosphate (IMP) and pyrophosphate, preventing excess amounts of ITP from forming. However, some ITPA mutants are unable to function properly, leading to various medical conditions and diseases caused by increased levels of ITP. One severe mutant, labeled R178C, modifies an arginine residue into cysteine at the 178th amino acid position. The R178C protein has reduced stability, but is able to bind to the substrate. However, it catalyzes the reaction at a much slower rate. This then leads to a fatal encephalopathy in newborns. It is imperative that R178C be studied to help create treatment options for this condition. To better study the R178C protein, magnesium chloride and pH assays of the protein were performed alongside wild type ITPA. The data was measured using high performance liquid chromatography. Assays showed that significant levels of magnesium are necessary for the function of both R178C and wild type ITPA. The pH optima of wild type ITPA was found to be 8.5 while R178C had the highest activity at a lower pH. This information will be used to make a standardized procedure for the development of a chemical screening assay for the discovery of molecules that stabilize R178C.
