Instituto de Agrobiotecnología del Litoral (UNL-CONICET), Facultad de Bioquímica y Ciencias Biológicas, Paraje "El Pozo" CC 242, S3000ZAA Santa Fe, Argentina.
Estación Experimental Agropecuaria Rafaela, Instituto Nacional de Tecnología Agropecuaria, Rafaela, Santa Fe, Argentina.
Biochimie. 2014 Apr;99:44-53. doi: 10.1016/j.biochi.2013.11.002. Epub 2013 Nov 14.
This paper addresses the identification, cloning, expression, purification and functional characterization of thioredoxin reductase from Babesia bovis, the etiological agent of babesiosis. The work deals with in vitro steady state kinetic studies and other complementary analyses of the thioredoxin reductase found in the pathogenic protist. Thioredoxin reductase from B. bovis was characterized as a homodimeric flavoprotein that catalyzes the NADPH-dependent reduction of Trx with a high catalytic efficiency. Moreover, the enzyme exhibited a disulfide reductase activity using DTNB as substrate, being this activity highly sensitive to inhibition by Eosin B. The thioredoxin reductase/thioredoxin system can reduce oxidized glutathione and S-nitrosoglutathione. Our in vitro data suggest that antioxidant defense in B. bovis could be supported by this enzyme. We have performed an enzymatic characterization, searching for targets for rational design of inhibitors. This work contributes to the better understanding of the redox biochemistry occurring in the parasite.
本文针对巴贝斯虫属（Babesia bovis）的硫氧还蛋白还原酶进行了鉴定、克隆、表达、纯化和功能特征分析，巴贝斯虫属是引起巴贝斯虫病的病原体。本工作对致病原生动物中发现的硫氧还蛋白还原酶进行了体外稳态动力学研究和其他补充分析。从 B. bovis 中分离出的硫氧还蛋白还原酶是一种同源二聚体黄素蛋白，能够高效地催化 NADPH 依赖型 Trx 还原。此外，该酶以 DTNB 为底物表现出二硫键还原酶活性，该活性对曙红 B 的抑制作用非常敏感。硫氧还蛋白还原酶/硫氧还蛋白系统可以还原氧化型谷胱甘肽和 S-亚硝基谷胱甘肽。我们的体外数据表明，B. bovis 的抗氧化防御可能依赖于该酶。我们进行了酶学特征分析，寻找合理设计抑制剂的靶点。这项工作有助于更好地理解寄生虫体内发生的氧化还原生物化学。
