Becker A, Dowdle E B, Hechler U, Kauser K, Donner P, Schleuning W D
Research Laboratories of Schering AG, Berlin, Germany.
FEBS Lett. 1993 Jan 2;315(1):100-3. doi: 10.1016/0014-5793(93)81142-m.
A new member of the endothelin/sarafotoxin family of vasoconstrictor peptides, bibrotoxin (BTX), was isolated from the venom of the burrowing asp Atractaspis bibroni by reversed-phase FPLC. The amino acid sequence of BTX differs from SRTX-b in the substitution Ala4 instead of Lys4, which suggests that it represents the peptide isoform of Atractaspis bibroni corresponding to SRTX-b. BTX competed for [125I]ET-1 binding to human ETB-type receptor with a Ki of 3.2 x 10(-9) M compared to 4.2 x 10(-9) M for SRTX-b. In rat thorax aorta BTX induced vasoconstrictions with a threshold concentration of 3 x 10(-8) M compared to 1 x 10(-9) for ET-1.
