An examination of the beta-glucosidase (linamarase) banding pattern in flax seedlings using Ferguson plots and sodium dodecyl sulphate-polyacrylamide gel electrophoresis.

ABSTRACT

The reported polyacrylamide gel electrophoresis banding pattern for the main beta-glucosidase (linamarase) component from flax seed consists of five bands, made up of 62.5 and 65 kDa subunits; this component has an estimated molecular weight of 570-670 kDa. The present study used Ferguson plots to estimate the molecular weight of each electrophoretic band, plus two additional bands which were detected. From low to high relative mobility, the seven bands formed a linear series with estimated molecular weights from 1200 to 245 kDa. Each was 160 kDa smaller, and less charged, than the preceding band. This 160 kDa difference between bands did not appear to be consistent with the reported subunit size. Each band produced a corresponding band on sodium dodecyl sulfate (SDS)-gels. The decreases in molecular weight between the bands on nondenaturing gels and their corresponding bands on SDS-gels were multiples of the 62-65 kDa value. However, the estimated molecular weights of the SDS bands themselves and of the differences between the SDS bands were, again, not consistent with the proposed subunit size. The results suggest that active forms of this enzyme may contain a second minor component (possibly a 30-35 kDa component) in addition to the 62.5 and 65 kDa subunits.