Immunocytochemical localization of conglutin and legumin-like globulin in developing and mature seeds of Lupinus albus L.

The distribution of two seed proteins, namely conglutin γ and a legumin-like globulin, in developing and mature seeds of Lupinus albus L. has been examined by immunocytochemistry and the concomitant modifications of their constituent polypeptides followed by SDS-PAGE. Both proteins were found within vacuolar protein bodies in various tissues of the cotyledons, although with some differences in the distribution patterns. The legumin-like protein was found to be deposited within the large storage parenchyma cells of the cotyledons in a manner similar to that reported for other storage proteins; little or no immunolabelling was associated with the cotyledonary epidermal and vascular parenchyma cells. In contrast conglutin γ was present in all cell types. A precursor of the legumin-like protein accumulated transiently in the developing cotyledon, but was subsequently modified by proteolytic cleavage. The onset of such modification was concomitant with a transition in the predominant vacuolar forms within the storage parenchyma cells. No precursor molecules of conglutin γ have been detected in this study, thus indicating that this protein is deposited in the protein bodies in its mature form.