ABSTRACT
Peptide hormones and neuropeptides must undergo a complex and highly regulated process of biosynthesis prior to secretion. This chapter describes Posttranslational events in the order in which they occur as precursors travel through the secretory pathway. The formation of correct disulfide bridging is a critical event in the biosynthesis of secretory and integral membrane proteins. Glycosylation of proteins destined for secretion is a common posttranslational event. Since attachment of oligosaccharides occurs prior to segregation to the secretory granule, this modification is a prime candidate for participation in sorting and targeting events. Phosphorylation and sulfation are posttranslational modifications like glycosylation that are confined to the endoplasmic reticulum (ER)/Golgi compartment. With the cloning, sequencing, and expression of several candidate prohormone cleavage enzymes or convertases, many aspects of peptide biosynthesis have been clarified. Many studies have provided clear evidence of prohormone structures promoting sorting to the regulated pathway of secretion.
