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Isolation and characterization of a new bradykinin potentiating octapeptide from gamma-casein
- Source :
- Canadian journal of physiology and pharmacology. 73(1)
- Publication Year :
- 1995
-
Abstract
- Peptides that display bradykinin-potentiating activity have been obtained from a number of distinct sources, such as snake venoms, fibrinogen, and casein. This paper describes the isolation and sequencing of a novel bradykinin-potentiating peptide, generated by tryptic hydrolysis of the γ-casein chain. No homology was found to other known vasoactive or vasopotentiating peptides. The octapeptide Tyr-Pro-Val-Gln-Pro-Phe-Thr-Glu, corresponding to the γ-casein(114–121) sequence, was isolated from the tryptic hydrolysis of γ-casein and also synthesized by solid-phase peptide synthesis. Both natural and synthetic peptides had the same retention time in HPLC and displayed a selective potentiating activity on isolated guinea-pig ileum for bradykinin and Lys-bradykinin but were not able to potentiate the effects of Met-Lys-bradykinin, Ile-Ser-bradykinin, angiotensin II, acetylcholine, or histamine. Intravenous injections of bradykinin and of bradykinin-potentiating octapeptide produced a persistent hypotension in conscious rats, a pattern that was not obtained when the octapeptide was replaced by captopril. This bradykinin-potentiating octapeptide is a strong competitive inhibitor of endo-oligopeptidase A (EC 3.4.24.15, formerly EC 3.4.22.19), but it has low inhibitory potency towards angiotensin-converting enzyme (EC 3.4.15.1). Thus, our results suggest that other peptidases in addition to angiotensin-converting enzyme, such as endo-oligopeptidase A, may contribute to the reduction of the effective concentration of bradykinin in the circulation.Key words: bradykinin, potentiating peptides, casein, endo-oligopeptidase A, angiotensin-converting enzyme, smooth muscle, rat arterial blood pressure.
- Subjects :
- medicine.medical_specialty
Physiology
Protein Hydrolysates
Guinea Pigs
Molecular Sequence Data
Bradykinin
Neuropeptide
Peptide
Angiotensin-Converting Enzyme Inhibitors
Blood Pressure
In Vitro Techniques
chemistry.chemical_compound
Uterine Contraction
Physiology (medical)
Internal medicine
Casein
medicine
Peptide synthesis
Animals
Trypsin
Amino Acid Sequence
Chromatography, High Pressure Liquid
Pharmacology
chemistry.chemical_classification
Hydrolysis
Caseins
Biological activity
General Medicine
Angiotensin II
Rats
Endocrinology
chemistry
Biochemistry
Chromatography, Gel
Female
Oligopeptides
Histamine
Muscle Contraction
Subjects
Details
- ISSN :
- 00084212
- Volume :
- 73
- Issue :
- 1
- Database :
- OpenAIRE
- Journal :
- Canadian journal of physiology and pharmacology
- Accession number :
- edsair.doi.dedup.....e28be2e8a76467385b79caa25a8a9b1c