Bombesin

Boltzmann equation Boltzmann relation Boltzman statistics Bolvidon Bolzano process Bombesin [31362-50-2]... 

The basic polymer appears to be a hydroxylated polyether to which octadecyl chains have been bonded and so it behaves as a reverse phase exhibiting dispersive interactions with the solutes. An example of the separation of a series of peptides is shown in figure 15. The column was 3.5 cm long, 4.6 mm i.d. The solutes shown were (1) oc-endorphin, (2) bombesin, (3) y-endorphin, (4) angiotensin, (5) somatostatin and (6) calcitonon. The separation was carried out with a 10 min linear program from water containing 0.2% trifluoroacetic acid to 80% acetonitrile. 

IC5Q — 3.4 pM gastrin-releasing peptide/bombesin receptor... 

S., Beglinger, C., and Eberle, A.N. A combinatorial peptoid library for the identification of novel MSH and GRP/ Bombesin receptor ligands. J. Receptor Signal Transduct. Res. 1999, 19, 449-466. 

Figure 2 shows the elution profiles of several neuropeptides and the PCP-like material. When the PCP-active fractions were rechromatographed over a flatter gradient and in a different solvent system, it was clear that bombesin- and substance P-immunoreactiv-ity no longer coeluted with the PCP-like material. 

Panel B Activity profiles of bombesin, neuropeptide Y, and substance p from the same HPLC fractions. 

Millar, J.B., and Rozengur, E. (1990) Chronic desensitization to bombesin by progressive down-regulation of bombesin receptors in Swiss 3T3 cells./. Biol. Chem. 265, 12052-12058. 

Finally, RNA editing can be involved, as in the case of the amphibian bombesin-like peptides, where nucleotides in the mRNA are changed and the final protein is not a direct reflection of the sequence encoded in the gene. RNA editing is also seen in the glutamate (Ch. 15) and serotonin receptors (Ch. 13 and Ch. 15) and probably will be found elsewhere as detection methods become more sophisticated. 

Aziridine cleavage based on an Sn2 reaction was used for the synthesis of peptides bearing E alkene dipeptide isosteres, a novel class of potent bombesin receptor antagonists [62]. Treatment of the vinylaziridine 86 (Scheme 9.19) with isobutyl and isopentyl magnesiocyanocuprates in THF at —78 °C for 30 min. stereospecifi-cally gave the desired E alkene isosteres 87 in high isolated yields [63]. 

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