Post-translational N-glycosylation of a truncated form of a peptide processing enzyme.
Peptidylglycine alpha-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-translational N-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-translational N-glycosylation.
Departments of Neuroscience and Physiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
A S
AS
Kolhekar
A S
AS
Quon
C A
CA
Berard
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Mains
B A
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Eipper
D000818:Animals; D001216:Asparagine / Q000378:metabolism; D001665:Binding Sites; D016466:CHO Cells; D006224:Cricetinae; D004721:Endoplasmic Reticulum / Q000378:metabolism; D006031:Glycosylation; D006602:Hexosyltransferases; D008565:Membrane Proteins; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000378:metabolism*; D009097:Multienzyme Complexes; D009844:Oligosaccharides / Q000378:metabolism; D010446:Peptide Fragments / Q000235:genetics / Q000378:metabolism*; D017510:Protein Folding; D011499:Protein Processing, Post-Translational; D011994:Recombinant Proteins / Q000378:metabolism; D014166:Transferases / Q000378:metabolism
D008565:Membrane Proteins; D009097:Multienzyme Complexes; D009844:Oligosaccharides; D010446:Peptide Fragments; D011994:Recombinant Proteins; D001216:Asparagine; D006899:Mixed Function Oxygenases; C035189:peptidylglycine monooxygenase; D014166:Transferases; D006602:Hexosyltransferases; C025620:dolichyl-diphosphooligosaccharide - protein glycotransferase