Programa Ofidismo/Escorpionismo, Universidad de Antioquia, Street 62 No. 52-59, A.A. 1226 Medellín, Colombia.
Toxicon. 2013 Mar 15;64:1-11. doi: 10.1016/j.toxicon.2012.11.027. Epub 2012 Dec 31.
An L-amino acid oxidase (LAAO) from Crotalus durissus cumanensis venom (CdcLAAO) was purified to homogeneity using a combination of size-exclusion and ion exchange chromatographies. CdcLAAO is a monomeric protein exhibiting an apparent molecular mass of 55 kDa and a calculated pI of 8. Its complete 498-amino-acid sequence was deduced through cDNA and protein sequencing. The enzyme oxidized L-Leu with K(m) and a V(Max) of 9.23 μM and 0.46 μM/min respectively, and exhibited Kcat and a Kcat/K(m) of 1.8 s(-1) and 195 mM(-1)s(-1). CdcLAAO inhibited in a dose-dependent manner the growth of Staphylococcus aureus and Acinetobacter baumannii. The inhibitory effect was more significant on S. aureus, with a Minimal Inhibitory Concentration (MIC) of 8 μg/mL and Minimal Bactericidal Concentration (MBC) of 16 μg/mL, than against A. baumannii, with a MIC of 16 μg/mL and MBC of 32 μg/mL. However, against Escherichia coli CdcLAAO did not show inhibitory capacity at the concentrations tested (2-128 μg/mL). CdcLAAO did not exhibit cytotoxic activity on the mouse myoblast cell line C(2)C(12) and on peripheral blood mononuclear cell (PBMC).
从矛头蝮蛇（Crotalus durissus cumanensis）毒液中纯化得到一种 L-氨基酸氧化酶（LAAO）（CdcLAAO），采用凝胶过滤层析和离子交换层析相结合的方法对其进行了纯化。CdcLAAO 是一种单体蛋白，表现出 55 kDa 的表观分子量和 8 的计算等电点。通过 cDNA 和蛋白质测序推导出其完整的 498 个氨基酸序列。该酶以 9.23 μM 的 K(m)和 0.46 μM/min 的 V(Max)氧化 L-Leu，表现出 1.8 s(-1)的 Kcat 和 195 mM(-1)s(-1)的 Kcat/K(m)。CdcLAAO 以剂量依赖性方式抑制金黄色葡萄球菌和鲍曼不动杆菌的生长。对金黄色葡萄球菌的抑制作用更为显著，其最小抑菌浓度（MIC）为 8 μg/mL，最小杀菌浓度（MBC）为 16 μg/mL，而对鲍曼不动杆菌的 MIC 和 MBC 分别为 16 μg/mL 和 32 μg/mL。然而，在测试的浓度（2-128 μg/mL）下，CdcLAAO 对大肠杆菌没有表现出抑制能力。CdcLAAO 对小鼠成肌细胞系 C(2)C(12)和外周血单个核细胞（PBMC）没有细胞毒性活性。
