Post-translational N-Glycosylation of a Truncated Form of a Peptide Processing Enzyme

• Published in: The Journal of biological chemistry 1998-09, Vol.273 (36), p.23012-23018
• Main Authors: Kolhekar, Aparna S., Quon, Andrew S.W., Berard, Carla A., Mains, Richard E., Eipper, Betty A.
• Format: Article
• Language: English
• Subjects: Animals; Asparagine - metabolism; Binding Sites; CHO Cells; Cricetinae; Endoplasmic Reticulum - metabolism; Glycosylation; Hexosyltransferases; Membrane Proteins; Mixed Function Oxygenases - genetics; Mixed Function Oxygenases - metabolism; Multienzyme Complexes; Oligosaccharides - metabolism; Peptide Fragments - genetics; Peptide Fragments - metabolism; Protein Folding; Protein Processing, Post-Translational; Recombinant Proteins - metabolism; Transferases - metabolism
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.273.36.23012

Peptidylglycine α-amidating monooxygenase (PAM) catalyzes the carboxyl-terminal amidation of bioactive peptides through a two-step reaction involving the monooxygenase and lyase domains. PAM undergoes endoproteolytic cleavage in neuroendocrine cells in the lyase domain. To determine which of the two possible paired basic sites is utilized, truncated PAM proteins ending at these sites were stably expressed in Chinese hamster ovary cells. While characterizing the truncation mutants, it became apparent that N-glycosylation occurred post-translationally at the single site localized near the carboxyl terminus of the lyase domain. The post-translationalN-glycosylation of this site does not require the newly synthesized protein to remain tightly bound to membranes. Both malfolded, secretion incompetent proteins and fully active, secreted proteins were subject to post-translationalN-glycosylation.