TIME-COURSE OF LECTIN AND STORAGE PROTEIN-BIOSYNTHESIS IN DEVELOPING PEA (PISUM-SATIVUM) SEEDS

Lectins and storage proteins from pea (Pisum sativum) and other Legumi nosae seeds interact in vitro. In order to evaluate whether this relat ionship may be important also in vivo, the time course of biosynthesis of these proteins in developing pea seeds was followed. The proteins appear in the following temporal order: vicilin - lectin - convicilin - legumin. The time course of protein synthesis was also followed by t he subcellular morphological changes occurring simultaneously. The app earance of vicilin coincides with the formation of regularly shaped pr otein globules within the vacuole. Immediately after the start of lect in synthesis, these globules flatten and begin to adhere to the inner membrane surface of the vacuole. Legumin appears at a time when the va cuoles already have largely disappeared in favour of smaller vesicles which eventually develop into protein bodies. These results together w ith previous findings are consistent with the view that one of the bio logical functions of the lectin may consist in serving as a link betwe en vicilin and the inner face of the vacuole membrane.