Elimination of Differences in the Mobility of Flax Isoperoxidases on PAGE by Digestion with alpha-Mannosidase.

In the flax (Linum usitatissimum) genotype Stormont cirrus, anodic peroxidases from the genotroph S migrate more slowly on PAGE and SDS-PAGE than the corresponding peroxidases from the genotroph L. When purified isoperoxidases S2 and L2 were digested with alpha-mannosidase, the difference in mobility was eliminated. Treatment with alpha-fucosidase and beta-xylosidase also altered the mobility of S2 and L2, but affected the sensitivity to the action of endo-beta-N-acetylglucosaminidase H of only S2. Our results suggest differences in posttranslational processing of the carbohydrate moiety between S and L isoperoxidases. These differences were also found in other S and L glycoenzymes (anodic acid phosphatases) as well as in the peroxidases of other flax genotypes.