Bradykinin and Kallidin

Several peptides isolated from the venom of the South American snake Bothrops jararaca are potent ACE inhibitors and were briefly used for the treatment of hypertension, but were soon superseded by surprisingly simple molecules with high inhibitory effect. At the Squibb Institute for Medical Research in Princeton, New Jersey, Miguel A. Ondetti (Plate 32) recognized that ACE is similar in its substrate specificity to the well studied protease car-boxypeptidase A. He designed, therefore, molecules that should fit into the active site of ACE (presumably similar to the active site of carboxypeptidase A) and form complexes with the enzyme. The dipeptide , 2-D-methyl-3-mercapto-propionyl-L-proline, captopril [7] strongly associated with the enzyme and 

The almost unique success of captopril stimulated extensive research in the area of enzyme inhibitors, since enzymes are implicated in many pathological conditions. Inhibition of the release of angiotensin still attracts considerable interest and many peptide-like pseudosubstrates are being constructed to serve as renin inhibitors. 

Incubation of a protein fraction from blood plasma with trypsin gives rise to peptides with conspicuous biological effects. Pain, dilation of peripheral blood vessels, increased coronary flow and enhanced capillary permeability were observed on administration of these protein fragments [8]. In the early sixties the nonapeptide bradykinin and its precursors, kallidin and methionyl-kalUdin were isolated in pure form and their amino acid sequences determined soon after. 

In the sequencing of bradykinin one of the proline residues was overlooked. The error was corrected both by a reexamination of the degradation study [9] and through experiments with peptides synthesized for this purpose [10]. From the various syntheses of bradykinin the scheme of Nicolaides and de Wald, stepwise chain-lengthening with active esters [11] is mentioned here. Also, bradykinin was the first biologically active peptide synthesized by the solid phase method [12] (Chap. 5). 

An important line of research was initiated by the study of the enzymatic inactivation of bradykinin [14]. Inhibitors of carboxypeptidases involved in the process appeared as potentiators of bradykinin and were then shown to be inhibitors of the angiotensin converting enzyme (ACE, cf. p. 182) as well. 

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Nearly all cells express kinin receptors that mediate the activities of both bradykinin and kallidin. The activation of these G-protein coupled receptors causes relaxation of venular smooth muscle and hypotension, increased vascular permeability, contraction of smooth muscle of the gut and airway leading to increased airway resistance, stimulation of sensory neurons, alteration of ion secretion of epithelial cells, production of nitric oxide, release of cytokines from leukocytes, and the production of eicosanoids from various cell types [11,12]. Because of this broad spectrum of activity, kinins have been implicated as an important mediator in many pathophysiologies including pain, sepsis, asthma, rheumatoid arthritis, pancreatitis, and a wide variety of other inflammatory diseases. Moreover, a recent report demonstrated that bradykinin B2 receptors on the surface of human fibroblasts were upregulated three-fold beyond normal in patients with Alzheimer s disease, implicating bradykinin as a participant in the peripheral inflammatory processes associated with that disease [13]. 

Muscle cells release kallikrein during inflammation causing formation of active kinin peptides (bradykinin and kallidin) from kininogen [65, 66]. Kinins are peptide hormones that produce vasodilation, increase capillary permeability, and cause pain and infiltration of neutrophils. There is a direct correlation between the amount of kinin in plasma or tissues and the degree of inflammation. Vascular dilation causes increased blood flow to infection [67, 68], Bik inhibits formation of kinins and vascular dilation by kallikrein, thereby inhibiting smooth muscle contraction [69-71],... 

Bradykinin is a vasoactive nonapeptide which is the most important mediator generated by the kinin system and it is involved in inflammation processes (Calixto et al, 2000). Kinins so far identified include bradykinin and kallidin. They cause local increases in the permeability of small blood vessels. Bradykinin is a potent stimulator of pain receptors in the skin and has a powerful influence on stimulating smooth muscle contraction, inducing hypotension, and increasing blood flow and permeability of capillaries Cyvetal, 2001). 

Bradykinin and kallidin ate potent vasodilators and hypotensive agents that have different peptide structures bradykinin is a nonapeptide, whereas kallidin is a decapepttde. Kdlidin is ly.syl-bradykinin that is. it has an additional lysine at the NH2 terminus of the chain. Tliese two compounds arc made available from kininogen. a hlood globulin, on hydrolysis. Trypsin, plasmin, or the proteases of certain snake venoms can catalyze the hydrolysis of kininogen. 

Thi ,DPhe BK [Thi ,DPhe ]-bradykinin. bradykinin-potentiating peptide teprotide. bradykinin potentiator B teprotide. BRADYKININ RECEPTOR AGONISTS act at sites recognizing members and derivatives of the bradykinin family of hormone peptides - kinins - of which bradykinin (BK) and kallidin (lysyl-bradykinin Lys-BK KD) are the main mammalian members. The bradykinin family is distinct from the tachykinin family of peptides, though both have profound hypotensive actions and contract many intestinal and other smooth muscles. Historically, it was noted that the former action was relatively slow-developing, hence the name bradykinin. Notable actions of bradykinin and kallidin are to dilate blood vessels and increase their permeability to plasma proteins, and to stimulate sensory nerve C-fibres. These actions are pro-inflammatory, and reflect the fact that the kinin-formation system is activated in inflammation, and enzymes (kallikreins) form the kinins from blood-borne or tissue precursors (kininogens) on injurious insult. 

Figure 4.3 Experimental competitive isotherm data (symbols) and best bi-Langmuir competitive isotherm (solid lines) for bradykinin and kallidin. Reproduced with permission from D. Zhou, K. Kacztmrski, G. Guiockon, ]. Chromatogr. A, 1015 (2003) 73 (Fig. 1).

Zhou et al. measured by FA the single-component isotherms of two related peptides, bradykinin and kallidin (MW 1060 and 1188, respectively) on a Zorbax SB Ci8 microbore column (Agilent Technologies), using a 20% aqueous solution of ACN (with 0.1% TFA) as the mobile phase [81]. The isotherm data were fitted to the Langmuir, the bi-Langmuir, the Langmuir-Frermdlich and the Toth isotherm... 

Figure 16.19 Comparison of the experimental (s3nnbols) overloaded elution band profiles of a mixture of the closely related peptides bradykinin and kallidin on a Zorbax SB-C18150 x 0.5 mm column eluted with ACN/H2O, 20/80 v/v (+ 0.5% TFA), for a loading factor Ly = 0.29% and the profiles calculated with the ED (solid lines) and the FOR models (dashed lines), (a) Parameters of the FOR model derived from conventional correlations, (b) Dm in the FOR model optimized numerically at 1 x 10 cm /s. Reproduced with permission from D. Zhou, X. Liu, K. Kaczmarski, A. Felinger, G. Guiochon, Biotech. Prog. 19 (2003) 945 (Figure 4.) 2003, American Chemical Society.

The human plasma metallo-protease carboxypeptidase N (CPN, arginine carboxypeptidase, anaphylatoxin inactivator, kininase I, EC 3.4.17.3) catalyzes the release of the basic amino acids lysine and arginine from the C-termini of peptides and proteins such as bradykinin and kallidin [95], the anaphylatoxins C3a, C4a, and C5a [96,97], fibrinopeptides 6A and 6D [98], hexapeptide enkephalins [99], protamine [100], and the creatine kinase MM-isoenzyme [101,102]. Its most likely physiological function is to protect the organism from the actions of potent peptides, which may escape from tissues or be released in the circulation. 

As autacoids, bradykinin and kallidin increase vascular permeability, produce vasodilation, increase the synthesis of prostaglandins, and cause edema and pain. Extensive evidence exists that bradykinin and other kallidin substances contribute to the pathogenesis of the inflammatory response that occurs in acute and chronic diseases including allergic reactions, arthritis, asthma, sepsis, viral rhinitis, and inflammatory bowel diseases (see Figure 30). 

FIGURE 30 Bradykinin and kallidin increase vascular permeability, produce vasodilation, increase the synthesis of prostaglandins, and cause edema and pain. 

A number of factors, including tissue damage, allergic reactions, viral infections, and other inflammatory events, activate a series of proteolytic reactions that generate bradykinin and kallidin in tissues. These peptides contribute to inflammatory responses as autacoids that act locally to produce pain, vasodilation, and increased vascular permeability. Much of their activity is due to stimulation of the release of potent mediators such as prostaglandins, NO, or endothelium-derived hyperpolarizing factor (EDHF). 

Numerous analogues of the hypotensive polypeptides bradykinin, kallidin, caerulein, eledoisin, and physalaemin have been prepared and tested in recent years. Bradykinin and kallidin are produced from plasma globulins by the influence of certain enzymes [73 a]. Eledoisin comes from the salivary glands of the... 

A cross-reactive sensor array based on luminescence changes has been reported by Severin and coworkers [74]. In this case no synthetic modifications were operated, but the sensing elements were created by mixing some metal complexes with fluorescent dyes. The complex formation between metal ions, such as Rh, Ru or Pd, quenches the dye fluorescence the peptide competes with the dye for metal ion complexation, removing it from the complex. The fluorescence turn on is the signal of the peptide interaction. The activation of fluorescence is also an indication of the equilibrium reported in Fig. 24 and it is the basis of the peptides discrimination. The sensor array was able to differentiate between several dipeptides at 20-50 X 10 M concentration higher oligopeptides, such as bradykinin and kallidin were also discriminated and the system was also able to differentiate between two dipeptides, carnosine and homocamosine, in a more complex environment such as human serum. 

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