Purification and characterization of protease III from Escherichia coli

Cheng, Y. S., Zipser, D. (June 1979) Purification and characterization of protease III from Escherichia coli. J Biol Chem, 254 (11). pp. 4698-706. ISSN 0021-9258 (Print)0021-9258 (Linking)

URL: http://www.ncbi.nlm.nih.gov/pubmed/374413


An endoproteolytic enzyme of Escherichia coli, designated protease III, has been purified about 9,600-fold to homogeneity with a 6% yield. The purified enzyme consists of a single polypeptide chain of Mr 110,000 and is most active at pH 7.4. Protease III is very sensitive to metal-chelating agents and reducing agents. The EDTA-inactivated enzyme can be reactivated by Zn2+, Co2+ or Mn2+. Protease III is devoid of activity toward aminopeptidase, carboxypeptidase, or esterase substrates but rapidly degrades small proteins. When fragments of beta-galactosidase are used as substrates for protease III, the enzyme preferentially degrades proteins with molecular weights of less than 7,000. Protease III cleaves the oxidized insulin B chain at two sites with an initial rapid cleavage at Tyr-Leu (16-17) and a second slower cut at Phe-Tyr (25-26).

Item Type: Paper
Uncontrolled Keywords: Cations, Divalent Drug Stability Endopeptidases/isolation & purification/*metabolism Escherichia coli/*enzymology Kinetics Molecular Weight Substrate Specificity
Subjects: organism description > bacteria > escherichia coli
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > enzymes > Protease
CSHL Authors:
Communities: CSHL labs
Depositing User: Matt Covey
Date: 10 June 1979
Date Deposited: 26 May 2016 16:35
Last Modified: 26 May 2016 16:35
Related URLs:
URI: https://repository.cshl.edu/id/eprint/32669

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