Cotranslational fatty acylation of mucus glycoprotein. Addition of palmitic acid to peptidyl-tRNA occurs prior to peptide chain completion and its release.
1. The fatty acylation of mucus glycoprotein nascent peptides was investigated using [3H]palmitic acid and [35S]methionine-labeled peptidyl-tRNA of rat gastric mucous cells. 2. The mucus glycoprotein peptidyl-tRNA fraction was found to contain covalently bound palmitic acid in its complexes. 3. RNase digestion of the mucus glycoprotein peptidyl-tRNA released [3H]palmitic acid labeled peptides which, on SDS-polyacrylamide gel, separated into a multitude of bands ranging in size from 2000 to 60,000 Da. 4. The analyses of low molecular weight peptides revealed that palmitic acid was present in methionine-labeled peptides containing 30-43 amino acids and those of 18-25 amino acids or larger devoid of methionine, but was not identified in methionine-labeled peptides containing 10-15 amino acids. 5. The results indicate that the N-terminal fatty acylation of mucus glycoprotein nascent peptides is a cotranslational process which is occurring in an immediate vicinity of the signal peptide fragment.
Slomiany
A
A
New Jersey Dental School, University of Medicine and Dentistry of New Jersey, Newark 07103-2425.
Tsukada
H
H
Zalesna
G
G
Slomiany
B L
BL
D000215:Acylation; D004591:Electrophoresis, Polyacrylamide Gel; D005227:Fatty Acids / Q000378:metabolism*; D005753:Gastric Mucosa / Q000166:cytology / Q000378:metabolism; D006023:Glycoproteins / Q000096:biosynthesis*; D006868:Hydrolysis; D007202:Indicators and Reagents / Q000378:metabolism; D008970:Molecular Weight; D019308:Palmitic Acid; D010169:Palmitic Acids / Q000378:metabolism*; D011132:Polyribosomes / Q000378:metabolism; D014176:Protein Biosynthesis; D012343:RNA, Transfer / Q000378:metabolism*; D012346:RNA, Transfer, Amino Acyl / Q000378:metabolism*; D012588:Scintillation Counting; D004124:p-Dimethylaminoazobenzene / Q000031:analogs & derivatives / Q000378:metabolism
D005227:Fatty Acids; D006023:Glycoproteins; D007202:Indicators and Reagents; D010169:Palmitic Acids; D012346:RNA, Transfer, Amino Acyl; C019037:tRNA, peptidyl-; D019308:Palmitic Acid; C010572:4-N,N-dimethylaminoazobenzene-4'-sulfonyl chloride; D012343:RNA, Transfer; D004124:p-Dimethylaminoazobenzene