Abstract
The biosynthesis and processing of cellulase from ripening avocado fruit was studied. The mature protein is a glycoprotein, as judged by concanavalin A binding, with a molecular weight of 54,200. Upon complete deglycosylation by treatment with trifluoromethane sulfonic acid the mature protein has a molecular weight of 52,800 whereas the immunoprecipitated in vitro translation product has a molecular weight of 54,000. This result indicates that cellulase is synthesized as a large molecular weight precursor, which presumably possesses a short-lived signal peptide. A membrane-associated and heavily glycosylated form of the protein was also identified. This putative secretory precursor was enzymically active and the carbohydrate side chains were sensitive to endoglycosidase H cleavage. Results of partial endoglycosidase H digestion suggest that this precursor form of the mature glycoprotein possesses two high-mannose oligosaccharide side chains. The oligosaccharide chains of the mature protein were insensitive to endoglycosidase H cleavage, indicating that transport of the membrane-associated cellulase to the cell wall was accompanied by modification of the oligosaccharide side chains. The presence of a large pool of endoglycosidase H-sensitive membrane-associated cellulase (relative to an endoglycosidase H-insensitive form) suggest that transit of this protein through the Golgi is rapid relative to transit through the endoplasmic reticulum.
Full text
PDF





Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Almin K. E., Eriksson K. E., Jansson C. Enzymic degradation of polymers. II. Viscometric determination of cellulase activity in absolute terms. Biochim Biophys Acta. 1967 Jul 11;139(2):248–253. doi: 10.1016/0005-2744(67)90029-0. [DOI] [PubMed] [Google Scholar]
- Anderson C. W., Straus J. W., Dudock B. S. Preparation of a cell-free protein-synthesizing system from wheat germ. Methods Enzymol. 1983;101:635–644. doi: 10.1016/0076-6879(83)01044-7. [DOI] [PubMed] [Google Scholar]
- Awad M., Young R. E. Postharvest Variation in Cellulase, Polygalacturonase, and Pectinmethylesterase in Avocado (Persea americana Mill, cv. Fuerte) Fruits in Relation to Respiration and Ethylene Production. Plant Physiol. 1979 Aug;64(2):306–308. doi: 10.1104/pp.64.2.306. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bollini R., Vitale A., Chrispeels M. J. In vivo and in vitro processing of seed reserve protein in the endoplasmic reticulum: evidence for two glycosylation steps. J Cell Biol. 1983 Apr;96(4):999–1007. doi: 10.1083/jcb.96.4.999. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Burnette W. N. "Western blotting": electrophoretic transfer of proteins from sodium dodecyl sulfate--polyacrylamide gels to unmodified nitrocellulose and radiographic detection with antibody and radioiodinated protein A. Anal Biochem. 1981 Apr;112(2):195–203. doi: 10.1016/0003-2697(81)90281-5. [DOI] [PubMed] [Google Scholar]
- Cathala G., Savouret J. F., Mendez B., West B. L., Karin M., Martial J. A., Baxter J. D. A method for isolation of intact, translationally active ribonucleic acid. DNA. 1983;2(4):329–335. doi: 10.1089/dna.1983.2.329. [DOI] [PubMed] [Google Scholar]
- Chen J., Varner J. E. An extracellular matrix protein in plants: characterization of a genomic clone for carrot extensin. EMBO J. 1985 Sep;4(9):2145–2151. doi: 10.1002/j.1460-2075.1985.tb03908.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Chrispeels M. J., Higgins T. J., Craig S., Spencer D. Role of the endoplasmic reticulum in the synthesis of reserve proteins and the kinetics of their transport to protein bodies in developing pea cotyledons. J Cell Biol. 1982 Apr;93(1):5–14. doi: 10.1083/jcb.93.1.5. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Chrispeels M. J., Sadava D. E. Synthesis and secretion of proteins in plant cells: the hydroxyproline-rich glycoprotein of the cell wall. Symp Soc Dev Biol. 1974;30(0):131–152. doi: 10.1016/b978-0-12-612973-1.50012-7. [DOI] [PubMed] [Google Scholar]
- Della-Penna D., Christoffersen R. E., Bennett A. B. Biotinylated proteins as molecular weight standards on Western blots. Anal Biochem. 1986 Feb 1;152(2):329–332. doi: 10.1016/0003-2697(86)90417-3. [DOI] [PubMed] [Google Scholar]
- Edge A. S., Faltynek C. R., Hof L., Reichert L. E., Jr, Weber P. Deglycosylation of glycoproteins by trifluoromethanesulfonic acid. Anal Biochem. 1981 Nov 15;118(1):131–137. doi: 10.1016/0003-2697(81)90168-8. [DOI] [PubMed] [Google Scholar]
- Goding J. W. Conjugation of antibodies with fluorochromes: modifications to the standard methods. J Immunol Methods. 1976;13(3-4):215–226. doi: 10.1016/0022-1759(76)90068-5. [DOI] [PubMed] [Google Scholar]
- Hawkes R., Niday E., Gordon J. A dot-immunobinding assay for monoclonal and other antibodies. Anal Biochem. 1982 Jan 1;119(1):142–147. doi: 10.1016/0003-2697(82)90677-7. [DOI] [PubMed] [Google Scholar]
- Hubbard S. C., Ivatt R. J. Synthesis and processing of asparagine-linked oligosaccharides. Annu Rev Biochem. 1981;50:555–583. doi: 10.1146/annurev.bi.50.070181.003011. [DOI] [PubMed] [Google Scholar]
- Ivarie R. D., Jones P. P. A rapid sensitive assay for specific protein synthesis in cells and in cell-free translations: use of Staphylococcus aureus as an adsorbent for immune complexes. Anal Biochem. 1979 Aug;97(1):24–35. doi: 10.1016/0003-2697(79)90322-1. [DOI] [PubMed] [Google Scholar]
- Laemmli U. K. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature. 1970 Aug 15;227(5259):680–685. doi: 10.1038/227680a0. [DOI] [PubMed] [Google Scholar]
- Markwell M. A., Haas S. M., Bieber L. L., Tolbert N. E. A modification of the Lowry procedure to simplify protein determination in membrane and lipoprotein samples. Anal Biochem. 1978 Jun 15;87(1):206–210. doi: 10.1016/0003-2697(78)90586-9. [DOI] [PubMed] [Google Scholar]
- Miyata S., Akazawa T. Enzymic mechanism of starch breakdown in germinating rice seeds : 12. Biosynthesis of alpha-amylase in relation to protein glycosylation. Plant Physiol. 1982 Jul;70(1):147–153. doi: 10.1104/pp.70.1.147. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Okita T. W., Decaleya R., Rappaport L. Synthesis of a possible precursor of alpha-amylase in wheat aleurone cells. Plant Physiol. 1979 Jan;63(1):195–200. doi: 10.1104/pp.63.1.195. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Pesis E., Fuchs Y., Zauberman G. Cellulase activity and fruit softening in avocado. Plant Physiol. 1978 Mar;61(3):416–419. doi: 10.1104/pp.61.3.416. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Schønheyder H., Andersen P. Effects of bovine serum albumin on antibody determination by the enzyme-linked immunosorbent assay. J Immunol Methods. 1984 Aug 3;72(1):251–259. doi: 10.1016/0022-1759(84)90453-8. [DOI] [PubMed] [Google Scholar]
- Stewart J. C. Colorimetric determination of phospholipids with ammonium ferrothiocyanate. Anal Biochem. 1980 May 1;104(1):10–14. doi: 10.1016/0003-2697(80)90269-9. [DOI] [PubMed] [Google Scholar]
- Tarentino A. L., Maley F. Purification and properties of an endo-beta-N-acetylglucosaminidase from Streptomyces griseus. J Biol Chem. 1974 Feb 10;249(3):811–817. [PubMed] [Google Scholar]