In:
Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 84, No. 11 ( 1987-06), p. 3685-3689
Abstract:
Ubiquitin is a protein of 76 amino acids found in every eukaryotic cell. Although ubiquitin is implicated in ATP-dependent nonlysosomal protein degradation and is also conjugated to specific cellular proteins, the role played by ubiquitin in cellular events has not been defined. We report that purified ubiquitin has intrinsic proteolytic activity and demonstrate that this activity is comparable to that of other well-characterized proteases. Monoclonal antibodies specific to ubiquitin inhibit proteolysis. Ubiquitin has protease activity over a broad pH range with an optimum at pH 8.0. It is stimulated by Ca2+ and is inhibited by high concentrations of phenylmethylsulfonyl fluoride and diisopropyl fluorophosphate. Ubiquitin will cleave proteins at a limited number of sites. We propose that the ubiquitination of a protein can convert that protein into an ad hoc specific protease and models are presented as to how this can play a role in regulating a variety of cellular events.
Type of Medium:
Online Resource
ISSN:
0027-8424
,
1091-6490
DOI:
10.1073/pnas.84.11.3685
Language:
English
Publisher:
Proceedings of the National Academy of Sciences
Publication Date:
1987
detail.hit.zdb_id:
209104-5
detail.hit.zdb_id:
1461794-8
SSG:
11
SSG:
12
