Date of Award
Master of Science (MS)
Department of Chemistry
Marjorie A. Jones
Leishmaniasis, as defined by the Center for Disease Control and Prevention, is a neglected tropical disease with 1.6 million new cases reported each year. However, there is yet to be safe, effective, and affordable treatments provided to those affected by this disease1. Still underappreciated as a potential pharmaceutical targets, especially for cutaneous leishmaniasis infections, are the two isozymes of secreted acid phosphatase (SAP); secreted acid phosphatase 1 (SAP1) and secreted acid phosphatase 2 (SAP2). These enzymes are involved in the survival of the parasite in the sand fly vector, and the prevention of host macrophages from forming parasitophorous vacuole and hydrogen peroxide 2,3. Thus, the kinetic behavior of these SAPs is of interest, and is reported here as a function of L. tarentolae age in culture. Vanadium (V5+), specifically the monomeric oxyanion orthovanadate (VO43-), is reported to be a competitive inhibitor of phosphatases 4,5,6,7,8,9. Orthovanadate serves as a known competitive inhibitor for the research presented here. The application of electric or electromagnetic fields as a medicinal therapeutic is not new 10. The utility of applying electric fields for the treatment of leishmaniasis is under studied, and the application of electric fields to Leishmania secreted acid phosphatases has not yet been reported 11. The results of such studies using L. tarentolae as a model system, with and without the addition of orthovanadate, are reported here. Furthermore, the effect specific electric fields have on the kinetic parameters of L. tarentolae SAPs are also reported.
1. Leishmaniasis. https://www.cdc.gov/parasites/leishmaniasis/epi.html (Accessed 20 Dec. 2016).
2. Fernandes, A. C.; Soares, D. C.; Saraiva, E. M.; Meyer-Fernandez, J. R.; Souto-Padron, T. “Different secreted phosphatase activites in Leishmania amazonensis. FEMS Microbiol Lett. 2013. 340(2):117-128.
3. Baghaei, M.; BAGHAEI, M. “Characterization of acid phosphatase in the promastigotes of three isolates of Leishmania major. Iran. J. Med. Sci. 2003. 28(1):1-8.
4. VanEtten, Rl.; Waymack, PP.; Rehkop, DM. Inhibition of myosin ATPase by vanadate ion. J. Am. Chem. 1974; (96): 6782-6785.
5. Abbott, SJ.; Jones, SR.; Weinman, SA.; Bockhoff, FM.; McLafferty, FW.; Knowles, JR. Chiral[16O, 17O, 18O]phosphate monoesters. Asymmetric synthesis and stereochemical analysis of [1(R)-16O, 17O, 18O]phosphor-(S)-propane-1,2-diol. J. Am. Chem. Soc. 1979; (101): 4323-4332.
6. Knowles, JR. Enzyme-catalyzed phosphoryl transfer reactions. Annu. Rev. Biochem 1980; (49): 877-919.
7. Gressor, MJ.; Tracey, AS.; Stankiewwicz, PJ.; In Advances in Protein Phosphatases; Merlev, W.; DiSalvo, J.Eds.; Leuven University Press, Belgum, 1987.
8. Gordon, JA. Use of vanadate as protein-phosphotyrosine phosphatase inhibitor. Methods Enzymol. 1991; (201): 477-482.
9. Li, M.; Ding, W.; Baruah, B.; Crans, DC.; Wang, R.; Inhibition of protein tyrosine phosphatases 1B and alkaline phosphatase by bis(maltolato)oxovanadium (IV). 2008; (102): 1846-1853.
10. Holden, K. R. Biological effects of pulsed electromagnetic field (PEMF) therapy. http://www.ondamed.net/us/biological-effects-of-pulsed-electromagnetic-field-pemf-therapy (Accessed 2 Feb. 2017).
11. Hejazi, H.; Eslami, G.; Dalimi, A. “The parasiticidal effect of electricity on Leishmania major, both in vitro and in vivo.” Annals of Tropical Medicine & Parasitology. 1972. 98(1): 37-42.
Dorsey, Benjamin M., "The Biochemical Assessment Of Two Secreted Acid Phosphatases From Leishmania Tarentolae, Their Response To Electric Fields, Glycosidase Incubation, And/or Vanadium" (2017). Theses and Dissertations. 804.