Date of Award


Degree Type


Degree Name

Master of Science




Dr. Mark A. Bernards

Second Advisor

Dr. Charlie Trick

Third Advisor

Dr. Mark Gijzen


Three ginsenoside-deglycosylating enzymes have been purified 13- to 25-fold, from Pythium irregulare culture filtrates, by a four-step purification protocol. The three glycosidases are relatively high molecular weight (a homodimer of 78 kDa subunits and two monomeric enzymes of 57 and 61 kDa), acidic proteins, sharing these properties with a series of other saponin-glycosidases. They were induced in cultures grown in the presence of ginsenosides and they have apparently, different glycosidic activities (1→6 versus 1→2). Primary sequence analysis identified them as glycosidases, but did not relate them to other saponin-deglycosylating enzymes. While no definite conclusions can be drawn regarding the involvement of these glycosidases in pathogenicity, it is possible that these enzymes help the oomycete find its host or obtain nutrients and/or growth factors from its environment. These are the first glycosidases purified from a Pythium species and provide a starting point for future characterization studies.



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