L-amino acid oxidase (Vipera ammodytes and Vipera berus) (LAAO)

L-amino acid oxidases (LAAOs) from Vipera ammodytes and Vipera berus are homodimeric flavoenzymes that constitute a significant portion of the venom proteome in these European vipers (UniProt P84842, Q6T6S5). These enzymes catalyze the oxidative deamination of L-amino acids, resulting in the production of alpha-keto acids, ammonia, and hydrogen peroxide (H2O2). The localized accumulation of H2O2 is the primary driver of the toxin's biological effects, including the induction of apoptosis, cytotoxicity, and interference with platelet aggregation (PMID: 25463100). In the context of envenomation, LAAOs contribute to tissue damage and inflammation, making them key targets for polyvalent and monovalent antivenoms such as ViperaTab. Beyond their role as toxins, these LAAOs are being investigated for their potent anti-tumor and antimicrobial properties, as they can selectively induce cell death in various cancer cell lines through oxidative stress pathways (PMID: 15621374). However, their high intrinsic toxicity and potential for non-specific oxidative damage remain significant challenges for therapeutic development.

Other names

L-amino-acid:oxygen oxidoreductase (deaminating)VamLAAOVbLAAOOphidian L-amino acid oxidaseAmmodytin L

Catalyzes the oxidative deamination of L-amino acids to produce alpha-keto acids, ammonia, and hydrogen peroxide; the resulting hydrogen peroxide induces oxidative stress and apoptosis in target cells.