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|Type:||Artigo de periódico|
|Title:||Pharmacological and partial biochemical characterization of Bmaj-9 isolated from Bothrops marajoensis snake venom|
Ponce-Soto, L. A.
Cruz-Hoefling, M. A.
|Abstract:||Bmaj-9, a basic PLA(2) (13679.33 Da), was isolated from Bothrops marajoensis snake venom through only one chromatographic step in reversed phase HPLC on mu-Bondapak C-18 column. The amino acid composition showed that Bmaj-9 had a high content of Lys, His, and Arg, typical of a basic PLA2. The sequence of Bmaj-9 contains 124 amino acid residues with a pl value of 8.55, such as DLWQWGQMIL KETGKLPFSY YTAYGCYCGW GGRGGKPKAD TDRCCFVHDC, revealing a high homology with Asp49 PLA2 from other snake venoms. It also exhibited a pronounced phospholipase A(2) activity when compared with crude venom. In chick biventer cervicis preparations, the time for 50% and 100% neuromuscular paralysis was respectively (in minutes): 110 +/- 10 (1 mu g/mL); 40 +/- 6 and 90 +/- 2 (5 mu g/mL); 30 +/- 3 and 70 +/- 5 (10 mu g/mL); 42 +/- 1 and 60 +/- 2 (20 mu g/mL), with no effect on the contractures elicited by either exogenous ACh (110 mu M) or KCl (20 mM). Bmaj-9 (10 mu g/mL) neither interfered with the muscular response to direct electrical stimulation in curarized preparations nor significantly altered the release of CK at 0, 15, 30 and 60 minutes incubations (27.4 +/- 5, 74.2 +/- 8, 161.0 +/- 21 and 353.0 +/- 47, respectively). The histological analysis showed that, even causing blockade at the maximum dosage (5 mu g/mL), the toxin does not induce significant morphological alterations such as necrosis or infiltration of inflammatory cells. These results identified Bmaj-9 as a new member of the basic Asp49 PLA(2) family able to interact with the motor nerve terminal membrane, thereby inducing a presynaptic neuromuscular blockade.|
|Appears in Collections:||FCM - Artigos e Outros Documentos|
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