Purification, Characterization and Biological Activity of an L-Amino Acid Oxidase from Trimeresurus mucrosquamatus Venom

WEI Ji-Fu1,2, WEI Qin1, LU Qiu-Min1, TAI Hong1, JIN Yang1, WANG Wan Yu1, XIONG Yu-Liang1*

( 1Department of Animal Toxicology, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming 650223, China;
2The Graduate School of the Chinese Academy of Sciences, Beijing 100039, China )

Abstract An L-amino acid oxidase (TM-LAO) from the venom of Hunan Trimeresurus mucrosquamatus was purified to homogeneity by three steps including DEAE Sephadex A-50 ion-exchange chromatography, Sephadex G-75 gel filtration and Resourse Q ion-exchange chromatography. TM-LAO is composed of two identical subunits with a molecular weight of 55 kD by SDS-polyacrylamide gel electrophoresis. The molecular weight was different with that of LAO purified from the same species distributed in Taiwan that was 70 kD. The 24 N-terminal amino acid sequence of TM-LAO is ADNKNPLEECFRETNYEEFLEIAR, which shares high similarity with other Viperid snake venom LAOs and has moderate similarity with Elapid snake venom LAOs. Further studies found that TM-LAO inhibited the growth of E. coli, S. aurues and B. dysenteriae. TM-LAO also showed cytotoxicity and platelet aggregation activity. All the biological activities were eliminated by catalase, a H2O2 scavenger. It shows that these biological effects are possibly due to the formation of H2O2 produced by TM-LAO.

Key words L-amino acid oxidase; Trimeresurus mucrosquamatus; antibacterial activity; cytotoxicity; platelet aggregation

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