Binding of (/sup 3/H)forskolin to platelet membranes and solubilized proteins from bovine brain
(/sup 3/H)Forskolin ((/sup 3/H)FSK) bound to platelet membranes with a Kd of 20 nM and a Bmax of 125 fmol/mg protein. The Bmax was increased to 400 fmol/mg protein in the presence of GppNHp (or NaF) and MgCl/sub 2/ with no change in Kd. PGE/sub 1/ decreased the EC50 of GppNHp to increase the Bmax for (/sup 3/H)FSK binding from 600 nM to 35 nM. In contrast, PGE/sub 1/ had no effect on the EC50 of NaF to increase (/sup 3/H)FSK binding. (/sup 3/H)FSK binding increased slowly over 60 min when forskolin and GppNHp were added to membranes simultaneously at 20/sup 0/C. Preincubation of membranes with GppNHp at 20/sup 5/C also caused a linear increase in adenylate cyclase specific activity over 60 minutes. (/sup 3/H)FSK bound to solubilized protein from bovine brain membrane with a Kd of 22 nM. GppNHp increased the number of binding sites in solubilized proteins only if membranes were not preincubated with GppNHp prior to solubilization. In conclusion the number of binding sites for (/sup 3/H)FSK is increased by agents that activate adenylate cyclase through the Ns protein. These sites appear to be associated with an activated complex of the Ns protein and adenylate cyclase.
- Research Organization:
- Center for Drugs and Biologics/FDA, Bethesda, MD
- OSTI ID:
- 5272793
- Report Number(s):
- CONF-8606151-; TRN: 86-031392
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:6; Conference: 76. annual meeting of the Federation of American Society for Experimental Biology, Washington, DC, USA, 8 Jun 1986
- Country of Publication:
- United States
- Language:
- English
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PROTEINS
BIOCHEMICAL REACTION KINETICS
RECEPTORS
BLOOD PLATELETS
BRAIN
CATTLE
CELL MEMBRANES
CYCLASES
TRACER TECHNIQUES
TRITIUM COMPOUNDS
ANIMALS
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY
BODY FLUIDS
CELL CONSTITUENTS
CENTRAL NERVOUS SYSTEM
DOMESTIC ANIMALS
ENZYMES
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
LYASES
MAMMALS
MATERIALS
MEMBRANE PROTEINS
MEMBRANES
NERVOUS SYSTEM
ORGANIC COMPOUNDS
ORGANS
REACTION KINETICS
RUMINANTS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques