Abstract
Fast protein liquid and ion-exchange chromatography, fluorescence, FT-IR spectra, and elemental and electrophoretic analyses were used to characterize proteins from seven species of Cactaceae, which can be divided into three groups based on their chemical and biochemical properties. Some cactus juice proteins precipitated by ammonium sulfate yielded complex electrophoretic patterns where the major bands cor- respond to approximately 24, 000 Da and 32, 000 Da in the presence of sodium dodecyl sulfate (SDS). The SDS-polyacrylamide gel electrophoretic (PAGE) patterns did not differ by the year of sample collection (1986 and 1992). Chromatographic analysis showed that protein characterization of cactus juices may be useful in cactus taxonomy at the family level. Fluorescence emission and FT-IR spectra of studied cacti species were measured to compare protein structure. Differences in the emission peak response and fluorescence intensity, as well as the changes in amide band content were found.
