Caracterização parcial e avaliação do potencial antibacteriano e antitumoral de uma L-aminoácido oxidase isolada de Bothrops jararacussu

• Autor(a) principal: Costa, Natália Cristina Santos
• Data de Publicação: 2012
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/2340
• topic: Bothrops jararacussu; L-aminoácido oxidase; Bactericida; Antitumoral; Bothrops jararacussu; L-amino acid oxidase; Bactericidal; Antitumor; CNPQ::CIENCIAS BIOLOGICAS::BIOLOGIA GERAL

Snake venoms are rich sources of proteins, enzymes and peptides, which represent 90% of the total constituents and probably are responsible for most of its biological effects. The L-amino acid oxidase (LAAO) is a component of venom and has antimicrobial, platelet aggregation-inducing, apoptoticinducing and anti-cancer activities. Considering the actions of the LAAOs, this work aims to characterize an isolated LAAO from crude venom of Bothrops jararacussu and evaluate its antibacterial and antitumor potential. The LAAO isolation involved three purification steps: an affinity chromatography on Con A-Sepharose column and two steps of ion exchange chromatography on MonoQ column. The protein purity was confirmed by SDS-PAGE and the obtained molecular mass was 68 kDa. The isolated LAAO showed higher affinity to L-Phe, followed by L-Met and L-Arg. The tryptic peptides profile revealed homology to other isolated LAAO from B. jararacussu, but the N-terminal sequence (ATNRNPLYYQFRRTDYFIF) displayed 56% identity with this enzyme, and therefore may be a new LAAO from B. jararacussu. The isolated LAAO showed antimicrobial activity against Gram-negative Proteus vulgaris (MIC 25 μg/mL, MBC 50 μg/mL) and Citrobacter freundii (MIC 100 μg/mL, MBC 100 μg/mL) and Gram-positive Listeria monocytogenes (MIC 25 μg/mL), Bacillus cereus (MIC 400 μg/mL), Bacillus subtilis (MIC 100 μg/mL, MBC 200 μg/mL) and Staphylococcus aureus (MIC 50 μg/mL, MBC 50 μg/mL), for which this enzyme was more effective than gentamicin. The LAAO displayed a cytotoxic effect of nearly 100% over two tumor cell lines studied (B16F10 and MDA-MB-231) when the enzyme was administrated at concentration 1 μg/mL. However the LAAO in this same concentration did not show any cytotoxic effect over human erythrocytes, which suggested that it s a multifunctional enzyme with therapeutic potential. The development of further studies involving this theme is necessary in order to enlarge enzyme characterization and to evaluate other potential bioactive actions.