Sarafotoxin S6c is a relatively weak displacer of specifically bound /sup 125/I-endothelin

Journal Article · Tue May 30 00:00:00 EDT 1989 · Biochem. Biophys. Res. Commun.; (United States)

DOI:https://doi.org/10.1016/0006-291X(89)91564-7· OSTI ID:5879296

Nayler, W G; Gu, X H; Casley, D J

Sarafotoxin S6a, S6b and S6c are chemically related vasoconstrictor polypeptides obtained from the venom of the snake, Atractaspis engaddensis. Each contains twenty one amino acid residues, two intrachain cysteine linkages and a long hydrophobic tail. Structurally these polypeptides resemble endothelin. Binding studies with /sup 125/I-endothelin showed that /sup 125/I-endothelin bound to rat ventricular membranes is totally displaceable by sarafotoxin S6b and endothelin, with IC50 values of 0.21 and 0.16 nM, respectively. Sarafotoxin S6c, which differs from sarafotoxin S6b in containing threonine instead of serine at residue 2, arginine instead of lysine at residue 4, and glutamic acid instead of lysine at residue 9, only weakly displaced bound /sup 125/I-endothelin (IC50, 854 nM). These results indicate that the ability of the sarafotoxins to interact with the endothelin binding site is not solely dependent on the long hydrophobic tail or the cysteine linkages.

• Research Organization: Univ. of Melbourne, Victoria (Australia)
• OSTI ID: 5879296
• Journal Information: Biochem. Biophys. Res. Commun.; (United States), Vol. 161:1
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
LIPIDS
RECEPTORS
POLYPEPTIDES
STRUCTURE-ACTIVITY RELATIONSHIPS
AMINO ACID SEQUENCE
BIOCHEMICAL REACTION KINETICS
CELL MEMBRANES
ENDOTHELIUM
HEART
IODINE 125
MICE
RATS
TRACER TECHNIQUES
VENOMS
ANIMAL TISSUES
ANIMALS
BETA DECAY RADIOISOTOPES
BODY
CARDIOVASCULAR SYSTEM
CELL CONSTITUENTS
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
MAMMALS
MEMBRANE PROTEINS
MEMBRANES
MOLECULAR STRUCTURE
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PEPTIDES
PROTEINS
RADIOISOTOPES
REACTION KINETICS
RODENTS
TISSUES
VERTEBRATES
550201* - Biochemistry- Tracer Techniques