| Autor: |
Gargosky, S E, Wallace, J C, Upton, F M, Ballard, F J |
| Zdroj: |
Biochemical Journal; October 1987, Vol. 247 Issue: 2 p427-432, 6p |
| Abstrakt: |
1. Synthetic peptides corresponding to the five, seven, nine and eleven C-terminal amino acids of the tetradecapeptide bombesin as well as bombesin itself and gastrin-releasing peptide have been evaluated in Swiss 3T3 cells in order to define the minimal peptide length needed for biological responsiveness. 2. Gastrin-releasing peptide, bombesin, the undecapeptide and nonapeptide had nearly equipotent abilities to compete for binding of labelled gastrin-releasing peptide to the cell receptors and showed half-maximal competition at 5-10 nM. The heptapeptide and pentapeptide were ineffective. 3. Cross-linking experiments demonstrated specific binding of gastrin-releasing peptide to a 100 kDa receptor subunit. 4. Total cell protein synthesis was stimulated equally by the nonapeptide and longer peptides with a half-maximal effect at 0.5 nM, while a more than 1000-fold higher concentration of the heptapeptide was required to produce a similar response. Comparable results were found when insulin was also present. 5. Neither an inhibition of protein breakdown nor a stimulation of DNA labelling could be demonstrated by bombesin or gastrin-releasing peptide. 6. We conclude that a C-terminal peptide ligand comprising more than seven but no more than nine amino acids is required to achieve high-affinity binding and receptor-mediated responses via the bombesin receptor. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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