Purification and characterization of protease Re, a cytoplasmic endoprotease in Escherichia coli
- 1 February 1988
- journal article
- research article
- Published by American Society for Microbiology in Journal of Bacteriology
- Vol. 170 (2), 921-926
- https://doi.org/10.1128/jb.170.2.921-926.1988
Abstract
Protease Re, a new cytoplasmic endoprotease in Escherichia coli, was purified to homogeneity by conventional procedures, using [3H]casein as the substrate. The enzyme consists of a single polypeptide of 82,000 molecular weight. It is maximally active between pH 7 and 8.5 and is independent of ATP. It has a pI of 6.8 and a Km of 10.8 microM for casein. Since diisopropyl fluorophosphate and phenylmethylsulfonyl fluoride inhibited this enzyme, it appears to be a serine protease. Protease Re was sensitive to inhibition by L-1-tosylamido-2-phenylethylchloromethylketone but not to that by 1-chloro-3-tosylamido-7-aminoheptanone, thiol-blocking reagents, chelating agents, or various peptide aldehydes. Re also degraded [125I]globin, [125I]glucagon, and 125I-labeled denatured bovine serum albumin to acid-soluble products (generally oligopeptides of greater than 1,500 daltons), but it showed no activity against serum albumin, growth hormone, insulin, or a variety of fluorometric peptide substrates. It also hydrolyzed oxidatively inactivated glutamine synthetase (generated by ascorbate, oxygen, and iron) four- to fivefold more rapidly than the native protein. Protease Re appears to be identical to the proteolytic enzyme isolated by Roseman and Levine (J. Biol. Chem. 262:2101-2110, 1987) by its ability to degrade selectively oxidatively damaged glutamine synthetase in vivo. Its role in intracellular protein breakdown is uncertain.This publication has 66 references indexed in Scilit:
- Selectivity of Intracellular Proteolysis: Protein Substrates Activate the ATP-Dependent Protease (La)Science, 1986
- E. coli contains eight soluble proteolytic activities, one being ATP dependentNature, 1981
- THE GENETICS OF PROTEIN DEGRADATION IN BACTERIAAnnual Review of Genetics, 1980
- The mechanism of protein secretion across membranesNature, 1980
- Interaction of Colicin E4 with Specific Receptor Sites Mediates Its Cleavage into Two Fragments Inactive Towards Whole CellsEuropean Journal of Biochemistry, 1979
- The Assembly of Proteins into Biological Membranes: The Membrane Trigger HypothesisAnnual Review of Biochemistry, 1979
- Intracellular Protein Degradation in Mammalian and Bacterial Cells: Part 2Annual Review of Biochemistry, 1976
- A Rapid and Sensitive Method for the Quantitation of Microgram Quantities of Protein Utilizing the Principle of Protein-Dye BindingAnalytical Biochemistry, 1976
- A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye bindingAnalytical Biochemistry, 1976
- Cleavage of Structural Proteins during the Assembly of the Head of Bacteriophage T4Nature, 1970