Bordonein-L, a new L-amino acid oxidase from Crotalus durissus terrificus snake venom: isolation, preliminary characterization and enzyme stability.
BACKGROUND
Crotalus durissus terrificus venom (CdtV) is one of the most studied snake venoms in Brazil. Despite presenting several well known proteins, its L-amino acid oxidase (LAAO) has not been studied previously. This study aimed to isolate, characterize and evaluate the enzyme stability of bordonein-L, an LAAO from CdtV.


METHODS
The enzyme was isolated through cation exchange, gel filtration and affinity chromatography, followed by a reversed-phase fast protein liquid chromatography to confirm its purity. Subsequently, its N-terminal amino acid sequence was determined by Edman degradation. The enzyme activity and stability were evaluated by a microplate colorimetric assay and the molecular mass was estimated by SDS-PAGE using periodic acid-Schiff staining and determined by mass spectrometry.


RESULTS
The first 39 N-terminal amino acid residues exhibited high identity with other snake venom L-amino acid oxidases. Bordonein-L is a homodimer glycoprotein of approximately 101 kDa evaluated by gel filtration. Its monomer presents around 53 kDa estimated by SDS-PAGE and 58,702 Da determined by MALDI-TOF mass spectrometry. The enzyme exhibited maximum activity at pH 7.0 and lost about 50 % of its activity after five days of storage at 4 °C. Bordonein-L's activity was higher than the control when stored in 2.8 % mannitol or 8.5 % sucrose.


CONCLUSIONS
This research is pioneering in its isolation, characterization and enzyme stability evaluation of an LAAO from CdtV, denominated bordonein-L. These results are important because they increase the knowledge about stabilization of LAAOs, aiming to increase their shelf life. Since the maintenance of enzymatic activity after long periods of storage is essential to enable their biotechnological use as well as their functional studies.
Department of Physics and Chemistry, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo (USP), Avenida do Café, s/n, Ribeirão Preto, 14040-903 SP Brazil.
Karla C F
KC
Bordon
Department of Physics and Chemistry, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo (USP), Avenida do Café, s/n, Ribeirão Preto, 14040-903 SP Brazil.
Gisele A
GA
Wiezel
Department of Pharmaceutical Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo (USP), Ribeirão Preto, SP Brazil.
Hamilton
H
Cabral
Department of Physics and Chemistry, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo (USP), Avenida do Café, s/n, Ribeirão Preto, 14040-903 SP Brazil.
Eliane C
EC
Arantes
Chromatography; Crotalus durissus terrificus; Enzyme activity; Enzyme stability; L-amino acid oxidase; Rattlesnake; Snake venom; Stabilization; Yellow venom