k-Binding and Degradation of [3H]Dynorphin A (1?8) and [3H]Dynorphin A (1?9) in Suspensions of Guinea Pig Brain Membranes
| Autor: | L.E. Robson, Maureen G. C. Gillan, Hans W. Kosterlitz, A.T. McKnight |
|---|---|
| Rok vydání: | 1985 |
| Předmět: |
Stereochemistry
Guinea Pigs Dynorphin Cleavage (embryo) Dynorphins Biochemistry Substrate Specificity Guinea pig Cellular and Molecular Neuroscience chemistry.chemical_compound polycyclic compounds medicine Animals Protease Inhibitors Binding Sites Membranes Chemistry Receptors Opioid kappa musculoskeletal neural and ocular physiology Temperature Brain Substrate (chemistry) Dynorphin A Captopril Peptide Fragments Benzomorphans Kinetics Membrane nervous system Receptors Opioid Degradation (geology) medicine.drug |
| Zdroj: | Journal of Neurochemistry. 45:1034-1042 |
| ISSN: | 1471-4159 0022-3042 |
| DOI: | 10.1111/j.1471-4159.1985.tb05520.x |
| Popis: | Following incubation of [3H]dynorphin A (1-8) and [3H]dynorphin A (1-9) with suspensions of guinea pig brain membranes, analysis of the supernatants by HPLC has shown that both peptides are degraded at 25 degrees C and at 0 degrees C. Bestatin and captopril reduce degradation at 0 degrees C but for a similar degree of protection at 25 degrees C arginine-containing dipeptides are also required. The effects of these peptidase inhibitors on the degradation profiles indicate that [3H]dynorphin A (1-8) has three main sites of cleavage: the Tyr1-Gly2, Arg6-Arg7, and Leu5-Arg6 bonds. With [3H]dynorphin A (1-9) as substrate the Arg7-Ile8 and Ile8-Arg9 bonds are also liable to cleavage. In binding assays, in contrast to the effects of peptidase inhibitors on the degradation of unbound [3H]dynorphin A (1-8) and [3H]dynorphin A (1-9), bestatin and captopril have little effect on the binding characteristics of the tritiated dynorphin A fragments at the kappa-site at 0 degrees C. However, at 25 degrees C binding is low in the absence of peptidase inhibitors. When binding at mu- and delta-sites is prevented, the maximal binding capacities of [3H]dynorphin A (1-8), [3H]dynorphin A (1-9), and [3H](-)-bremazocine at the kappa-site are similar; [3H]dynorphin A (1-9) has 5-10 times higher affinity for the kappa-site than [3H]dynorphin A (1-8). Comparison of the effects of peptidase inhibitors on unbound dynorphin A fragments with their effects in binding assays suggests that the bound peptides are protected from the action of peptidases. |
| Databáze: | OpenAIRE |
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