RESUMO
Hemorphins are biologically active peptides, derived from hemoglobin, which presents a number of physiological activities. Proteolytic generation of these peptides is not fully understood; however, among their roles, is to provoke reduction on blood pressure. In this work, this particular biological effect was chosen as the monitor for the selection of mammalian vasoactive peptides. By combining high-performance liquid chromatography and mass spectrometry, including 'de novo' sequencing, several hemorphin-like peptides were identified presenting bradykinin potentiating activity. Moreover, taking LVV-hemorphin-7 as model compound, we evaluated its biological effect on blood pressure of anaesthetized rats. By summarizing all the results, it is possible to present the hemorphins as a family of proteolytically generated peptides that are able to potentiate bradykinin activity in vivo.
Assuntos
Bradicinina/fisiologia , Química Encefálica , Hemoglobinas/química , Pâncreas/química , Fragmentos de Peptídeos/farmacologia , Peptídeos/isolamento & purificação , Sequência de Aminoácidos , Animais , Bioensaio , Pressão Sanguínea/efeitos dos fármacos , Bradicinina/agonistas , Bradicinina/farmacologia , Cães , Sinergismo Farmacológico , Feminino , Cobaias , Hemoglobinas/isolamento & purificação , Hemoglobinas/farmacologia , Íleo/efeitos dos fármacos , Masculino , Dados de Sequência Molecular , Técnicas de Cultura de Órgãos , Fragmentos de Peptídeos/isolamento & purificação , Peptídeos/farmacologia , Ratos , Ratos Wistar , Ovinos , Regulação para Cima/efeitos dos fármacosRESUMO
The salivary complex of leeches contains many components able to modulate physiological mechanisms, such as coagulation and fibrinolysis, and it is composed by the salivary glands and proboscis, encompassing two different proteomes. The bidimensional electrophoretic pattern of the salivary complex from the Haementeria depressa leech revealed a total of 352 spots, 103 in common with the muscular tissue and 249 exclusive from the salivary complex as detected by silver staining; these spots showed isoelectric points from 3.5 to 9.5 and covered an apparent molecular weight range from 10 to 105 kDa. The following isoforms of proteins were identified by mass spectrometry analysis: antiplatelet protein, myohemerythrin and carbonic anhydrase. Since the leeches were not fed for about 2-3 months to stimulate the secretion of proteins that facilitates the blood metabolism, these most abundant proteins in the salivary complex excised from leeches, are expected to play a role during feeding and might have some anti-hemostatic properties. Furthermore, by zymography, a gelatinolytic and a fibrinolytic protein were identified.
Assuntos
Sanguessugas/química , Proteínas e Peptídeos Salivares/isolamento & purificação , Sequência de Aminoácidos , Animais , Anidrases Carbônicas/genética , Anidrases Carbônicas/isolamento & purificação , Eletroforese em Gel Bidimensional , Hemeritrina/genética , Hemeritrina/isolamento & purificação , Sanguessugas/genética , Sanguessugas/fisiologia , Dados de Sequência Molecular , Mapeamento de Peptídeos , Glândulas Salivares/química , Glândulas Salivares/fisiologia , Proteínas e Peptídeos Salivares/química , Proteínas e Peptídeos Salivares/genética , Proteínas e Peptídeos Salivares/fisiologia , Homologia de Sequência de Aminoácidos , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por MatrizRESUMO
Sarafotoxins (SRTXs) constitute a family of vasoactive peptides that were initially isolated from the venom of Atractaspis engaddensis, and that are structurally and functionally related to endothelins (ETs). Analysis of the venom of Atractaspis microlepidota microlepidota revealed several new SRTX molecules manifesting some new structural and functional characteristics. These novel SRTXs are longer by three amino acids than the previously described SRTXs, and are designated here "long-SRTXs". Six isoforms, derived from new poly-cistronic precursors, have been identified so far in the venom of this snake. One of these isoforms, designated SRTX-m, was chemically synthesized and its biological properties were studied. Our results show that SRTX-m induces toxicity in mice, mostly due to vasoconstriction, and also that it has a lower toxicity and potency than the more potent SRTX described up to now: sarafotoxin-b (SRTX-b) from A. engaddensis.