Interactions of insulin mimetic vanadium compounds with the sarcoplasmic reticulum calcium pump

INOR 819

Teresa Tiago, ttiago@ualg.pt1, Fernando Henao2, Ricardo Gândara3, Rui Duarte4, JJG. Moura4, D. C. Crans5, and Manuel Aureliano, maalves@ualg.pt6. (1) CCMar, Depto. Química e Bioquímica - FCT, Universidade do Algarve, Campus Gambelas, Faro, 8005-139, Portugal, (2) Depto. Bioquimica y Biologia Molecular, Facultad Ciencias, Universidad de Extremadura, Badajoz, 06071, Spain, (3) Depto. Química e Bioquímica - FCT, Universidade do Algarve, Campus Gambelas, Faro, 8005-139, Portugal, (4) REQUIMTE-CQFB - FCT, Universidade Nova de Lisboa, Caparica, 2829-516, Portugal, (5) Department of Chemistry, Colorado State University, Fort Collins, CO 80523, (6) CCMar/Depto. Química e Bioquímica - FCT, Universidade do Algarve, Campus Gambelas, Faro, 8005-139, Portugal
Sarcoplasmic reticulum Ca2+-ATPase (SR) is one of the proteins known to interact with vanadium. To this end, research efforts were launched with three vanadium compounds, namely pyridine-2,6-dicarboxylate-vanadium(V) (PDC), oxovanadium(IV)-bis(maltolato) (BMOV) and amavadine, potentially able to interact with the calcium-pump. The Ca2+-ATPase activity is affected differently by the complexes being the relative order of inhibition PDC > BMOV > Amavadine, with IC50 values of 25 µM¸ 40 µM and 325 µM, respectively, whilst an IC50 of 100 µM was obtained for metavanadate. Both the NMR signal of PDC and the EPR signals of BMOV and amavadine are affected upon SR addition suggesting an interaction with the protein. Upon dilution in the reaction medium, PDC is partially hydrolyzed and BMOV oxidized, whereas amavadine is stable. Concluding, these results reveal an interesting behaviour of vanadium complexes in aqueous media toward the modulation of a biological target involved in calcium homeostasis.
 

5th International Symposium on Chemistry and Biological Chemistry of Vanadium: Posters in Biochemistry and Chemistry
7:00 PM-10:00 PM, Tuesday, 12 September 2006 Moscone Center -- Hall D, Poster

Sci-Mix
8:00 PM-10:00 PM, Monday, 11 September 2006 Moscone Center -- Hall D, Sci-Mix

Division of Inorganic Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006