Membrane-associated proteolytic activity in Escherichia coli that is stimulated by ATP

Conference · Thu May 01 04:00:00 EDT 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:5126900

Klemes, Y; Voellmy, R W; Goldberg, A L

The degradation of proteins in bacteria requires metabolism energy. One important enzyme in this process is protease La, a soluble ATP-dependent protease encoded by the lon gene. However, lon mutants that lack a functional protease La still show some ATP-dependent protein breakdown. The authors have reported an ATP-stimulated endoproteolytic activity associated with the inner membrane of E. coli. This ATP-stimulated activity is found in normal levels in membranes derived from lon mutants, including strains carrying insertions in the lon gene. The membrane-bound activity hydrolyzes /sup 14/C-methylglobin at a linear rate for up to 3 hours. These fractions also contain appreciable proteolytic activity that is not affected by ATP. The stimulation by ATP requires the presence of Mg/sup 2 +/. Nonhydrolyzable ATP analogs (e.g. AMPPNP or ATP-..gamma..-S) and ADP do not enhance proteolysis. Unlike protease La, the membrane-associated enzyme does not degrade the fluorometric substrate, Glt-Ala-Ala-Phe-MNA, in an ATP-stimulated fashion, and its level is not influenced by high temperature of by the gene which regulates the heat-shock response. The enzyme is inhibited by dichloroisocoumarin and certain peptide chloromethyl ketones. They conclude that E. coli contain at least two ATP-dependent proteases with distinct specificities: one is soluble and the other is membrane-associated.

• Research Organization: Harvard Medical School, Boston, MA
• OSTI ID: 5126900
• Report Number(s): CONF-8606151-
• Conference Information: Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 45:6
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
550701 -- Microbiology-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALKALINE EARTH METAL COMPOUNDS
ATP
BACTERIA
BIOCHEMICAL REACTION KINETICS
CARBON 14 COMPOUNDS
CELL CONSTITUENTS
CELL MEMBRANES
CHEMICAL REACTIONS
COUMARIN
DECOMPOSITION
ENZYME ACTIVITY
ENZYMES
ESCHERICHIA COLI
ESTERS
GENES
HETEROCYCLIC COMPOUNDS
HYDROLASES
ISOTOPE APPLICATIONS
KETONES
KINETICS
LABELLED COMPOUNDS
LACTONES
MAGNESIUM COMPOUNDS
MEMBRANES
MICROORGANISMS
MUTANTS
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PEPTIDE HYDROLASES
PROTEOLYSIS
PYRANS
REACTION KINETICS
TRACER TECHNIQUES