What is pea legumin - Is it glycosylated?

Since there is some question as to whether or not legumin is glycosylated, this storage protein was isolated by various procedures from developing cotyledons of Pisum sativum L. supplied with [(14)C]-labeled glucosamine and analyzed by sodium dodecylsulfate-polyacrylamide gel electrophoresis. Legumin isolated by the classical method of Danielsson [(1949) Biochem. J. 44, 387-400] a procedure in which globulins extracted with a buffered salt solution are precipitated with ammonium sulfate (70% saturation) and legumin separated from vicilin by isoelectric precipitation, was labeled. The glucosamine incorporated into legumin was associated with low-molecular-weight polypeptides. In contrast, legumin isolated by the method of Casey [(1979) Biochem. J. 177, 509-520], a procedure where legumin is prepared by zonal isoelectric precipitation from globulins precipitated with 40-70% ammonium sulfate, was not labeled. However, the globulin fraction precipitated with 40% ammonium sulfate was labeled and the radioactive glucosamine was associated with low-molecular-weight polypeptides. Legumin isolated from protein bodies [Thomson et al. (1978) Aust. J. Plant Physiol. 5, 263-279] was not extensively labeled. However, the saltinsoluble fraction of protein body extracts was labeled and the radioactivity was associated with low-molecular-weight polypeptides. These results indicate that protein bodies contain a glycoprotein of low-molecular-weight that co-purifies with legumin isolated by the method of Danielsson but that is discarded when isolation methods developed more recently are used.