Characterization of VIP-receptors solubilized from lung

Conference · Tue Mar 04 23:00:00 EST 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:7119549

Paul, S; Said, S I

Vasoactive Intestinal Peptide (VIP) exerts multiple biologic actions through binding to specific receptors. The authors have solubilized VIP-receptors from guinea pig lung by the detergent CHAPS and separated the soluble receptors by high performance gel-filtration into two fractions. The binding of (/sup 125/I)-VIP to the two fractions was time-dependent, reversible and saturable. Kd for the 6.2 nm- and 2.3 nm-fractions were, respectively, 0.3 nM and 0.9 ..mu..M. GTP inhibited VIP-binding to the 6.2 nm-, but not the 2.3 nm-species. The GTP-treated 6.2 nm-fraction showed two classes of binding sites with lower affinity (Kd: 4.4 nM and 153 nM). In increased detergent concentration (9 mM), 46% of the binding-activity of the 6.2 nm species appeared in the 2.3 nm-fraction. The homologous peptides PHI and GRF, were, respectively, 87.5-fold and 22.9-fold less reactive than VIP with the 6.2 nm-complex. GRF was 22.7-fold more reactive and PHI was 31.1-fold less reactive than VIP with the 2.3 nm-species. The binding by the 6.2 nm-fraction was decreased by phospholipases A/sub 2/ (73%) and C (58%), but both enzymes increased binding by the 2.3 nm fraction (61-106%). In conclusion: (1) GTP-binding regulatory proteins are functionally coupled to the VIP-binding subunit in the 6.2 nm fraction, (2) the 2.3 nm-fraction is a dissociation product of the 6.2 nm-complex, (3) the change in the relative reactivity of VIP and GRF with the two receptor fractions may reflect differential regulation of receptor affinity by G-proteins and (4) bound phospholipids may modulate VIP receptor-number and affinity.

• Research Organization: Univ. of Oklahoma Health Science Center, Oklahoma City
• OSTI ID: 7119549
• Report Number(s): CONF-8604222-
• Journal Information: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Vol. 45:4; ISSN FEPRA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AFFINITY
ANIMALS
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BODY
CARBOXYLESTERASES
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
ENZYMES
ESTERASES
GUINEA PIGS
HYDROLASES
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LIPASE
LUNGS
MAMMALS
MEMBRANE PROTEINS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PEPTIDES
PROTEINS
PURIFICATION
RADIOISOTOPES
REACTION KINETICS
RECEPTORS
RESPIRATORY SYSTEM
RODENTS
TIME DEPENDENCE
TRACER TECHNIQUES
VERTEBRATES