Abstract
The heat-stable polypeptide ATP-dependent proteolysis factor 1 (APF-1) of the reticulocyte proteolytic system forms covalent compounds with proteins in an ATP-requiring reaction. APF-1 and lysozyme, a good substrate for ATP-dependent proteolysis, form multiple conjugates, as was shown by comigration of label from each upon gel electrophoresis. Multiple bands were also seen with other substrates of the ATP-dependent proteolytic system, such as globin or alpha-lactalbumin. Analysis of the ratio of APF-1 to lysozyme radioactivities and of the molecular weights of the bands indicated that they consist of increasing numbers of the APF-1 polypeptide bound to one molecule of lysozyme. The covalent linkage is probably of an isopeptide nature, because it is stable to hydroxylamine and alkali, and polylysine is able to give conjugates of APF-1. Removal of ATP after formation of the 125I-labeled APF-1 conjugates with endogenous proteins caused the regeneration of APF-1, indicating presence of an amidase. This reaction is thought to compete with proteases that may act on APF-1-protein conjugates, especially those containing several APF-1 ligands. A sequence of reactions in which the linkage of APF-1 to the substrate is followed by the proteolytic breakdown of the substrate is proposed to explain the role of ATP.
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- Botbol V., Scornik O. A. Degradation of abnormal proteins in intact mouse reticulocytes: accumulation of intermediates in the presence of bestatin. Proc Natl Acad Sci U S A. 1979 Feb;76(2):710–713. doi: 10.1073/pnas.76.2.710. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ciechanover A., Heller H., Elias S., Haas A. L., Hershko A. ATP-dependent conjugation of reticulocyte proteins with the polypeptide required for protein degradation. Proc Natl Acad Sci U S A. 1980 Mar;77(3):1365–1368. doi: 10.1073/pnas.77.3.1365. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ciehanover A., Hod Y., Hershko A. A heat-stable polypeptide component of an ATP-dependent proteolytic system from reticulocytes. Biochem Biophys Res Commun. 1978 Apr 28;81(4):1100–1105. doi: 10.1016/0006-291x(78)91249-4. [DOI] [PubMed] [Google Scholar]
- Etlinger J. D., Goldberg A. L. A soluble ATP-dependent proteolytic system responsible for the degradation of abnormal proteins in reticulocytes. Proc Natl Acad Sci U S A. 1977 Jan;74(1):54–58. doi: 10.1073/pnas.74.1.54. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Goldberg A. L., St John A. C. Intracellular protein degradation in mammalian and bacterial cells: Part 2. Annu Rev Biochem. 1976;45:747–803. doi: 10.1146/annurev.bi.45.070176.003531. [DOI] [PubMed] [Google Scholar]
- Hershko A., Ciechanover A., Rose I. A. Resolution of the ATP-dependent proteolytic system from reticulocytes: a component that interacts with ATP. Proc Natl Acad Sci U S A. 1979 Jul;76(7):3107–3110. doi: 10.1073/pnas.76.7.3107. [DOI] [PMC free article] [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]
- Murakami K., Voellmy R., Goldberg A. L. Protein degradation is stimulated by ATP in extracts of Escherichia coli. J Biol Chem. 1979 Sep 10;254(17):8194–8200. [PubMed] [Google Scholar]
- Roberts J. W., Roberts C. W., Mount D. W. Inactivation and proteolytic cleavage of phage lambda repressor in vitro in an ATP-dependent reaction. Proc Natl Acad Sci U S A. 1977 Jun;74(6):2283–2287. doi: 10.1073/pnas.74.6.2283. [DOI] [PMC free article] [PubMed] [Google Scholar]
- SIMPSON M. V. The release of labeled amino acids from the proteins of rat liver slices. J Biol Chem. 1953 Mar;201(1):143–154. [PubMed] [Google Scholar]