Identification and properties of very high affinity brain membrane-binding sites for a neurotoxic phospholipase from the taipan venom
- Centre de Biochimie, Nice (France)
Four new monochain phospholipases were purified from the Oxyuranus scutellatus (taipan) venom. Three of them were highly toxic when injected into mice brain. One of these neurotoxic phospholipases, OS2, was iodinated and used in binding experiments to demonstrate the presence of two families of specific binding sites in rat brain synaptic membranes. The affinities were exceptionally high, Kd1 = 1.5 +/- 0.5 pM and Kd2 = 45 +/- 10 pM, and the maximal binding capacities were Bmax 1 = 1 +/- 0.4 and Bmax 2 = 3 +/- 0.5 pmol/mg of protein. Both binding sites were sensitive to proteolysis and demonstrated to be located on proteins of Mr 85,000-88,000 and 36,000-51,000 by cross-linking and photoaffinity labeling techniques. The binding of {sup 125}I-OS2 to synaptic membranes was dependent on Ca2+ ions and enhanced by Zn2+ ions which inhibit phospholipase activity. Competition experiments have shown that, except for beta-bungarotoxin, a number of known toxic snake or bee phospholipases have very high affinities for the newly identified binding sites. A good correlation (r = 0.80) was observed between toxicity and affinity but not between phospholipase activity and affinity.
- OSTI ID:
- 5564636
- Journal Information:
- Journal of Biological Chemistry; (USA), Vol. 264:19; ISSN 0021-9258
- Country of Publication:
- United States
- Language:
- English
Similar Records
Biochemistry of snake venom neurotoxins and their application to the study of synapse. [Neurotoxins isolated from venom of the Formosan banded krait]
Identification, characterization, and developmental regulation of embryonic benzodiazepine binding sites
Related Subjects
LIPASE
RECEPTORS
CHEMICAL PROPERTIES
AFFINITY
AMINO ACID SEQUENCE
BIOCHEMICAL REACTION KINETICS
BRAIN
CALCIUM COMPOUNDS
CATIONS
CELL MEMBRANES
CHROMATOGRAPHY
CROSS-LINKING
ELECTROPHORESIS
ENZYME ACTIVITY
FRACTIONATION
IODINE 125
MICE
MOLECULAR WEIGHT
NERVE CELLS
POTASSIUM
REAGENTS
SERINE PROTEINASES
SODIUM
TRACER TECHNIQUES
TRYPSIN
VENOMS
ZINC COMPOUNDS
ALKALI METALS
ALKALINE EARTH METAL COMPOUNDS
ANIMAL CELLS
ANIMALS
BETA DECAY RADIOISOTOPES
BODY
CELL CONSTITUENTS
CENTRAL NERVOUS SYSTEM
CHARGED PARTICLES
CHEMICAL REACTIONS
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
ELEMENTS
ENZYMES
HYDROLASES
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
IONS
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
MAMMALS
MEMBRANE PROTEINS
MEMBRANES
METALS
MOLECULAR STRUCTURE
NERVOUS SYSTEM
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PEPTIDE HYDROLASES
POLYMERIZATION
PROTEINS
RADIOISOTOPES
REACTION KINETICS
RODENTS
SEPARATION PROCESSES
SOMATIC CELLS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques