Solubilization and Activity Detection in Polyacrylamide Gels of a Membrane-Bound Esterase from an Oenological Strain of Saccharomyces Cerevisiae

Due to the importance of esters in determining wine aroma, the presence of different esterases in soluble and insoluble cell fractions of an oenological strain of Saccharomyces cerevisiae was studied. Cells of an oenological yeast strain were separated into three fractions corresponding to the cytoplasm, periplasm and plasma membrane, all showing esterase activity. The conditions for optimal solubilization of the membrane-bound esterase were found, as well as those allowing its electrophoretic analysis, using the detergent disodium-n-lauryl-β-iminodipropionate (Deriphat) in the cathodic buffer. Comparison of the activity bands detected on gels revealed the presence of different esterase isoforms in the three sub-cellular fractions. The method can also be used as the first electrophoretic step in two-dimensional PAGE. Therefore, the procedures described are also a promising tool for the study of the yeast enzymes in relation to their effects during winemaking.