Peptides and Glycopeptides with Anti-Acetylcholinesterase Activity Obtained from Yeast Mannoproteins

Purified mannoproteins from 5 yeast strains belonging to the genera Brettanomyces, Candida, Pichia and Saccharomyces were studied. Each mannoprotein extract was hydrolysed with proteolytic enzymes, generating small peptides whose inhibitory activity against acetylcholinesterase (AChE) was determined. Partial purification of six selected mannoprotein extracts was done by reversed phase chromatography, six fractions with relevant inhibitory activity being obtained. Chromatographic and spectroscopic analyses revealed mainly hydrophilic peptides, with molecular weight between 700 and 4800 Da. The presence of sugars in all fractions was determined, mannose being the most abundant one. Subsequently, the most active fractions were again separated by affinity chromatography, which led to two new types of fractions: peptidic fractions (PFs) and glycopeptidic fractions (GPFs). Results showed that all fractions inhibited AChE, although GPFs inhibited AChE to a greater degree than PFs, with a percentage of inhibition ranging from 49.3 to 77.8%. Likewise, all GPFs fractions had higher values of inhibition than the corresponding whole fraction, while PFs showed lower percentages of anti-acetylcholinesterase activity. These results suggest that glycopeptidic are the most interesting fractions for their ability to inhibit this enzyme. As a conclusion, it was shown that some peptides produced by hydrolysis of mannoproteins proved able to inhibit AChE and should be considered as potential anti-AChE agents and significant to the manufacturing of food with potential functional properties