Artículos de revistas
Studies on ATP-diphosphohydrolase nucleotide-binding sites by intrinsic fluorescence
Fecha
2000Registro en:
Brazilian Journal of Medical and Biological Research, Volumen 33, Issue 7, 2018, Pages 725-729
0100879X
10.1590/S0100-879X2000000700001
Autor
Kettlun, A. M.
Espinosa, V.
Zanocco, A.
Valenzuela, M. A.
Institución
Resumen
Potato apyrase, a soluble ATP-diphosphohydrolase, was purified to homogeneity from several clonal varieties of Solanum tuberosum. Depending on the source of the enzyme, differences in kinetic and physicochemical properties have been described, which cannot be explained by the amino acid residues present in the active site. In order to understand the different kinetic behavior of the Pimpernel (ATPase/ ADPase = 10) and Desirée (ATPase/ADPase = 1) isoenzymes, the nucleotide-binding site of these apyrases was explored using the intrinsic fluorescence of tryptophan. The intrinsic fluorescence of the two apyrases was slightly different. The maximum emission wavelengths of the Desirée and Pimpernel enzymes were 336 and 340 nm, respectively, suggesting small differences in the microenvironment of Trp residues. The Pimpernel enzyme emitted more fluorescence than the Desirée apyrase at the same concentration although both enzymes have the same number of Trp residues. The binding of the nonhydro