Abstract
1. Cycloheximide inhibited immediately the incorporation of L-[4,5-3H]leucine and D-]2-3H]mannose into mammary proteins, suggesting that the mannosylation of mammary glycoproteins requires the continued supply of newly synthesized polypeptides. 2. The incorporation of radioactivity from N-acetyl-D-[1-14C] glucosamine into protein was not inhibited until approx. 30 min after cycloheximide addition. Much (greater than 90%) of this radioactivity was present as N-acetylgalactosamine. 3. N-Glycosylation appears to be inhibited immediately by cycloheximide due to a lack of newly synthesized acceptor polypeptides, whereas O-glycosylation continues for 30 min, the time taken for acceptor peptides to move from their site of synthesis to the Golgi region and for completion of glycosylation. 4. There was a transient increase in the incorporation of mannose into lipid-linked oligosaccharide in the presence of cycloheximide, followed by a decrease in the radioactivity in this fraction. 5. The major lipid-linked oligosaccharide extracted from explants incubated for 2h in the presence of cycloheximide (6-7 monosaccharide units) was smaller than that extracted from control explants (10-12 monosaccharide units).
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Bergman L. W., Kuehl W. M. Addition of glucosamine and mannose to nascent immunoglobulin heavy chains. Biochemistry. 1977 Oct 4;16(20):4490–4497. doi: 10.1021/bi00639a025. [DOI] [PubMed] [Google Scholar]
- Kiely M. L., McKnight G. S., Schimke R. T. Studies on the attachment of carbohydrate to ovalbumin nascent chains in hen oviduct. J Biol Chem. 1976 Sep 25;251(18):5490–5495. [PubMed] [Google Scholar]
- LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
- Rothman J. E., Lodish H. F. Synchronised transmembrane insertion and glycosylation of a nascent membrane protein. Nature. 1977 Oct 27;269(5631):775–780. doi: 10.1038/269775a0. [DOI] [PubMed] [Google Scholar]
- Schmitt J. W., Elbein A. D. Inhibition of protein synthesis also inhibits synthesis of lipid-linked oligosaccharides. J Biol Chem. 1979 Dec 25;254(24):12291–12294. [PubMed] [Google Scholar]
- Speake B. K., Dils R., Mayer R. J. Regulation of enzyme turnover during tissue differention. Studies on the effects of hormones on the turnover of fatty acid synthetase in rabbit mammary gland in organ culture. Biochem J. 1975 May;148(2):309–320. doi: 10.1042/bj1480309. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Speake B. K., White D. A. The effect of tunicamycin on the glycosylation of lactating-rabbit mammary glycoproteins. Biochem J. 1979 Jun 15;180(3):481–489. doi: 10.1042/bj1800481. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Speake B. K., White D. A. The formation of lipid-linked sugars as intermediates in glycoprotein synthesis in rabbit mammary gland. Biochem J. 1978 Feb 15;170(2):273–283. doi: 10.1042/bj1700273. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Spiro M. J., Spiro R. G., Bhoyroo V. D. Lipid-saccharide intermediates in glycoprotein biosynthesis. I. Formation of an oligosaccharide-lipid by thyroid slices and evaluation of its role in protein glycosylation. J Biol Chem. 1976 Oct 25;251(20):6400–6408. [PubMed] [Google Scholar]
- TREVELYAN W. E., PROCTER D. P., HARRISON J. S. Detection of sugars on paper chromatograms. Nature. 1950 Sep 9;166(4219):444–445. doi: 10.1038/166444b0. [DOI] [PubMed] [Google Scholar]
- White D. A. The formation of lipid-linked sugars by cell-free preparations of lactating rabbit mammary gland. Biochem J. 1978 Mar 15;170(3):479–486. doi: 10.1042/bj1700479. [DOI] [PMC free article] [PubMed] [Google Scholar]