Separation and Partial Purification of 1,3-beta-Glucan and 1,4-beta-Glucan Synthases from Saprolegnia

Enriched 1,3-beta-glucan and 1,4-beta-glucan synthase fractions from the fungus Saprolegnia were isolated by rate zonal centrifugation on glycerol gradient. Purification was improved by entrapment of the enzymes in their reaction product, i.e. microfibrillar glucans. 1,3-beta-Glucan synthases were separated from 1,4-beta-glucan synthases following resuspension of entrapped enzymes. Sodium dodecylsulfate-polyacrylamide gel electrophoresis indicated that 1,3-beta-glucan and 1,4-beta-glucan synthases may have a different polypeptide composition because they were enriched for different protein subunits (34, 48, and 50 kD for the 1,3-beta-glucan synthase and 60 kD for the 1,4-beta-glucan synthase).