Bombesin (BN) is a tetradecapepide (Pyro-ENR LGN QWA VGH LM-amide) that was originally isolated from frog skin.
Several BN-related peptides have been isolated from amphibians and classified into three subfamilies: Bombesin, ranatensin, and phyllolitorin based upon the last three C-terminal residues.
Two BN-like peptides have been identified in mammals: NMB (neuromedin B) in the ranatensin family and GRP (gastrin-releasing peptide) in the BN-family.
BN-family of G-protein coupled receptors include at least four receptor subtypes: The GRP-preferring receptors (GRP-R or bb2), the NMB-preferring receptors (NMB-R or bb1) and Bombesin receptor subtype 3 (BRS-3 or bb4).
These receptors share approx.
50% amino acid homology and bind bombesin.
However, BRS-3 has much lower affinity for BN than GRP-R and NMB-R.
Mammalian BN-like peptides are widely distributed in the brain and gastrointestinal tract, where they modulate smooth-muscle contraction, exocrine and endocrine activities, metabolism and behavior.
Most recently, BRS-3 deficient mice have been shown to develop mild obesity, associated with hypertension, and impairment of glucose metabolism, reduced metabolic rate, increased feeding efficiency and subsequent hyperphagia.
Human BRS-3 gene (chromosome x) encodes a 399 aa protein with seven transmembrane domains.
The NH2 and COOH-termini are predicted to be extracellular and cytoplasmic, respectively.
Applications:Suitable for use in ELISA.
Western Blot, though not tested, may potentially be used as an application.
