The Synthesis of Ricinus communis Agglutin

摘要: Polyadenylated RNA isolated from the endosperm tissue of maturing castor been seeds was translated in a call-free rabbit reticulocyte lysate syste. Rabbit antibodies raised against Ricinus communis agglutinin were used to identify nascent chains. In contrast authentic polypeptides with molecular weights 31000 (A chains) and 37000 (glycosylated B chains), immunoreactive translational products Mr 33500 59000 observed. The inclusion canine pancreatic microsomes system resulted contranslational segregation these into lumen vesicles their modification, 32000 66000–69000 respectively. These size modifications cleavage leader sequences and, case larger product, concomittant core glycosylation. 32000-Mr 66000–69000-Mr proteins also observed amonst initially formed during labeling intact vivo, together 37000-Mr 39000-Mr proteins. Pulse-chase experiments showed that slowly disappeared while smaller further cleaved chains (authentic A chain), 34000 glycosylated chains). It concluded R. synthesized precursor form, possibly as ‘giant’ chain, on membrane-bound polysomes. Contranslational translocation across endoplasmic reticulum membrane accompanied by proteolysis remove where appropriate, Even after processing still form. Processing appeared occur posttranslationally.