J. Venom. Anim. Toxins incl. Trop. Dis.

Vol.9, No.2, p.491, 2003.

Poster - ISSN 1678-9199.

 

MOLECULAR CHARACTERIZATION AND ACTIVITY ON PLATELET AGGREGATION OF THREE PHOSPHOLIPASES A2 OF Bothops atrox VENOM

 

López-Lozano, J. L.(1,3), Sánchez, E.F.(2), Maria, W.S.(2),  Sousa, M.V.(3), Ricart, C.A.O.(3), Muniz, E.G.(1), Bührnheim, P.F.(1), Morhy, L.(3)

 

(1)Instituto de Medicina Tropical de Manaus, AM, (2)FUNED, MG, (3)CBSP, Universidade de Brasília, Brasília, DF, Brazil.

 

Bothrops venoms contain phospholipases A2 (PLA2) isoforms with different biological activities. Snake venom PLA2 can  induce effects on human platelet aggregation. In this study, we are reporting partial molecular characterization and activity on human platelet aggregation of three PLA2 of Bothrops atrox venom from Manaus region-Brazil. Three PLA2s, named Bam-PLA2-I, Bam-PLA2-II and Bam-PLA2-III, were purified. The molecular mass (by electro spray ionization mass spectrometry), N-terminal amino acid sequence, isoelectric point, PLA2 activity and  activity on human platelet aggregation, induce by ADP, were determinated to each PLA2. In table 1 and 2 are sumarized molecular characteristics of the PLA2s B. atrox venom.

 

Table 1. N-terminal aminoacid sequence of PLA2s Bothrops atrox venom.

 

S L V E L G K M I L Q E T G K N P V T S

N L W Q F G K M I N E E M G K F A F L N

N L W Q F E M L I K Q I A G R S G I L Y

Bam-PLA2-I

Bam-PLA2-II

Bam-PLA2-III

 

Table 2. Molecular characteristics of PLA2s Bothrops atrox venom.

 

PLA2

Molecular mass (Da)

pI

PLA2activity

U/mg proteína

Bam-PLA2-I

Bam-PLA2-II

Bam-PLA2-III

13832

13719

13739

9.0

8.3

9.0

-

4250

1196

(-) = PLA2 activity not detected.

 

Only Bam-PLA2-II showed inhibitory activity of human platelets aggregation induced by ADP (10 mM, final concentration), in a dose - and - time dependent manner (IC50% = 14,2mg).

Conclusions. Molecular analyses of N-terminal amino acid sequence and PLA2 activity suggest that Bam-PLA2-I is a PLA2-Lys49, but Bam-PLA2-II and Bam-PLA2-III are PLA2-Asp49, and inhibitory activity of PLA2s on human platelet aggregation induced by ADP could be not associated with PLA2 activity.

 

CORRESPONDENCE TO:

Jorge Luis López Lozano, Conjunto Colina de Aleixo. Rua 17 Quadra F Casa 68, Manaus, AM, CEP: 69083-600, Brasil, Email: luisiam@hotmail.com