Characterization of a membrane-associated serine protease in Escherichia coli

Journal Article · Wed Apr 01 04:00:00 EST 1987 · J. Bacteriol.; (United States)

OSTI ID:5903751

Palmer, S M; John, A C

Three membrane-associated proteolytic activities in Escherichia coli were resolved by DEAE-cellulose chromatography from detergent extracts of the total envelope fraction. On the basis of substrate specificity for the hydrolysis of chromogenic amino acid ester substrates, the first two eluting activities were determined previously to be protease V and protease IV, respectively. The third proteolytic activity eluting from the DEAE-cellulose column was further purified by affinity chromatography on benzamidine-Sepharose 6B. They termed this enzyme protease VI. Protease VI did not hydrolyze any of the chromogenic substrates used in the detection of protease IV and protease V. However, all three enzymes generated acid-soluble fragments from a mixture of E. coli membrane proteins which were biosynthetically labeled with radioactive amino acids. The activity of protease VI was sensitive to serine protease inhibitors. Using (/sup 3/H)diisopropylfluorophosphate as an active-site labeling reagent, they determined that protease VI has an apparent molecular weight of 43,000 in polyacrylamide gels. All three membrane-associated serine proteases were insensitive to inhibition by Ecotin, an endogenous, periplasmic inhibitor of trypsin.

• Research Organization: Rutgers, The State Univ. of New Jersey, Piscataway
• OSTI ID: 5903751
• Journal Information: J. Bacteriol.; (United States), Journal Name: J. Bacteriol.; (United States) Vol. 169:4; ISSN JOBAA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
550701 -- Microbiology-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
BACTERIA
CHEMICAL REACTIONS
DECOMPOSITION
ENZYME ACTIVITY
ENZYMES
ESCHERICHIA COLI
HYDROLASES
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MICROORGANISMS
PEPTIDE HYDROLASES
PROTEOLYSIS
SERINE PROTEINASES
TRACER TECHNIQUES
TRITIUM COMPOUNDS