Snake venom L-amino acid oxidases (LAAOs) are flavoenzymes with diverse physiological and pharmacological effects. These enzymes are found to showcase anticoagulant, antiplatelet, cytotoxicity and other biological effects in bite victims. However, the exact mechanism through which they exhibit several biological properties is not yet fully understood. The current study focussed on the purification of cobra venom LAAO and the functional characterization of purified LAAO. A novel L-amino acid oxidase NNLAAO70 with a molecular weight ~70 kDa was purified from the venom of an Indian spectacled cobra (Naja naja). NNLAAO70 showed high substrate specificity for L-His, L-Leu, and L-Arg during its LAAO activity. It inhibited adenosine di-phosphate (ADP) and collagen-induced platelet aggregation process in a dose-dependent manner. About 60% inhibition of collagen-induced and 40% inhibition of ADP-induced platelet aggregation was observed with a 40 μg/ml dose of NNLAAO70. NNLAAO70 exhibited bactericidal activity on Bacillus subtilis, Escherichia coli, Bacillus megaterium, and Pseudomonas fluorescens. NNLAAO70 also showed cytotoxicity on A549 cells in vitro. It showed severe bactericidal activity on P. fluorescens and lysed 55% of cells. NNLAAO70 also exhibited drastic cytotoxicity on A549 cells. At 1 μg/ml dosage, it demonstrated a 60% reduction in A549 viability and induced apoptosis upon 24-h incubation. H₂O₂ released during oxidative deamination reactions played a major role in NNLAAO70-induced cytotoxicity. NNLAAO70 significantly increased intracellular reactive oxygen species (ROS) levels in A549 cells by six fold when compared to untreated cells. Oxidative stress-mediated cell injury is the primary cause of NNLAAO70-induced apoptosis in A549 cells and prolonged oxidative stress caused DNA fragmentation and activated cellular secondary necrosis.

蛇毒L-氨基酸氧化酶（LAAO）是具有多种生理和药理作用的黄素酶。这些酶被发现对咬伤受害者具有抗凝血、抗血小板、细胞毒性和其他生物效应。然而，它们表现出多种生物学特性的确切机制尚未完全清楚。目前的研究重点是眼镜蛇毒LAAO的纯化和纯化LAAO的功能表征。从印度眼镜蛇 ( Naja naja ) 的毒液中纯化出一种分子量约为 70 kDa 的新型 L-氨基酸氧化酶 NNLAAO70。NNLAAO70 在其 LAAO 活性过程中对 L-His、L-Leu 和 L-Arg 显示出高底物特异性。它以剂量依赖性方式抑制二磷酸腺苷（ADP）和胶原诱导的血小板聚集过程。使用 40 μg/ml 剂量的 NNLAAO70 观察到，对胶原诱导的血小板聚集有约 60% 的抑制作用，对 ADP 诱导的血小板聚集有 40% 的抑制作用。NNLAAO70 对枯草芽孢杆菌、大肠杆菌、巨大芽孢杆菌和荧光假单胞菌具有杀菌活性。NNLAAO70还在体外对A549细胞表现出细胞毒性。它对荧光假单胞菌表现出强烈的杀菌活性，并裂解 55% 的细胞。NNLAAO70 对 A549 细胞也表现出强烈的细胞毒性。在 1 μg/ml 剂量下，A549 活力降低 60%，并在 24 小时孵育后诱导细胞凋亡。氧化脱氨反应过程中释放的H ₂ O ₂在NNLAAO70诱导的细胞毒性中起主要作用。与未处理的细胞相比，NNLAAO70 使 A549 细胞的细胞内活性氧 (ROS) 水平显着增加六倍。氧化应激介导的细胞损伤是NNLAAO70诱导A549细胞凋亡的主要原因，长期氧化应激导致DNA断裂和激活的细胞继发性坏死。