Modulation of 5-lipoxygenase by hydroperoxides and glutathione peroxidase

Conference · Sat Mar 01 04:00:00 EST 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:5524572

Bryant, R W; She, H S; Ng, K; Siegel, M I

In order to identify regulatory steps in leukotriene synthesis, the biochemical characteristics of a 5-lipoxygenase activity in a murine mast cell clone (MC-9) were investigated. Supernatants (100,000xg) of sonicated cells metabolized /sup 14/C-arachidonic acid to leukotriene B4 (LTB/sub 4/), diastereiomeric 5,12-dihydroxy-eicosatetraenoic acids (5,12-diHETEs), 5-hydroperoxy- and 5-hydroxy-eicosatetraenoic acids (5-HPETE and 5-HETE) and 5-oxo-eicosatetraenoic acid which were identified by high performance liquid chromatography (HPLC) and gas chromatograph-mass spectrometry (GC/MS). Lipoxygenase activity had a pH optimum of 6.9 and was highly dependent upon added calcium. The concentration of calcium for 50% activation (EC/sub 50/) was 3..mu..M. Activity was also stimulated by ATP (EC/sub 50/ = 160 ..mu..M). Lipoxygenase activity exhibited a biphasic concentration dependence for arachidonic acid with maximum product formation occurring at 35 ..mu..M. The activity showed apparent lag phase kinetics which were more pronounced at low protein levels (0.8 mg/ml). The lag phase was also greatly accentuated by glutathione (1 mM) plus glutathione peroxidase (0.4 units/ml). In contrast, addition of any of several hydroperoxides, i.e. 5-, 8-, 9-, or 15-HPETEs (EC/sub 50/ 1 ..mu..M), shortened the lag phase. The results suggest that the cellular levels of hydroperoxides and glutathione peroxidase, as well as calcium and certain nucleotides, may be important factors regulating leukotriene synthesis.

• Research Organization: Schering Corp., Bloomfield, NJ
• OSTI ID: 5524572
• Report Number(s): CONF-8604222-
• Conference Information: Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 45:3
• Country of Publication: United States
• Language: English

Related Subjects

550201 -- Biochemistry-- Tracer Techniques
560301* -- Chemicals Metabolism & Toxicology-- Cells-- (-1987)
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ALKALINE EARTH METALS
ANIMAL CELLS
ANIMALS
ARACHIDONIC ACID
ATP
BIOCHEMISTRY
BIOLOGICAL EFFECTS
BIOSYNTHESIS
CALCIUM
CARBON 14 COMPOUNDS
CARBOXYLIC ACIDS
CARDIOVASCULAR AGENTS
CELL CULTURES
CHEMISTRY
CHROMATOGRAPHY
CLONE CELLS
CONNECTIVE TISSUE CELLS
DRUGS
EICOSANOIC ACID
ELEMENTS
ENZYME ACTIVITY
ENZYMES
GAS CHROMATOGRAPHY
GLUTATHIONE
HYDROGEN COMPOUNDS
HYDROGEN PEROXIDE
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LIQUID COLUMN CHROMATOGRAPHY
MAMMALS
MASS SPECTROSCOPY
MAST CELLS
METABOLISM
METALS
MICE
MONOCARBOXYLIC ACIDS
NUCLEOTIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
OXIDOREDUCTASES
OXYGEN COMPOUNDS
OXYGENASES
PEPTIDES
PEROXIDASES
PEROXIDES
POLYPEPTIDES
PROTEINS
RADIOPROTECTIVE SUBSTANCES
RODENTS
SEPARATION PROCESSES
SOMATIC CELLS
SPECTROSCOPY
SYNTHESIS
TRACER TECHNIQUES
VASOCONSTRICTORS
VERTEBRATES