期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1982
卷号：79
期号：21
页码：6566-6568
DOI：10.1073/pnas.79.21.6566
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：During the biosynthesis of secretory proteins, an NH2-terminal peptide, referred to as a signal peptide, is cotranslationally cleaved off after the protein enters the cisternal space of the endoplasmic reticulum. It also has been reported that the core glycosylation reaction of some secretory and viral membrane glycoproteins occurs as a cotranslational event. However, despite a huge amount of work, no decisive answer has been given as to the temporal sequence of proteolytic cleavage of the signal peptide and glycosylation on the polysomes for any secretory or membrane glycoprotein. We show here that proteolytically processed and already glycosylated chains of rice seed alpha-amylase exist on the polysomes; furthermore, our results provide direct evidence that glycosylation is preceded by proteolytic processing during the biosynthesis of the alpha-amylase molecule.
