a School of Marine and Technology , Harbin Institute of Technology , Weihai , Shandong , P.R. China.
Bioengineered. 2017 Nov 2;8(6):742-749. doi: 10.1080/21655979.2017.1373534. Epub 2017 Sep 21.
A glutathione peroxidase (GPx) gene, designated as PsGPx, was cloned from Antarctic psychrotrophic bacterium Pseudoalteromonas sp. ANT506 and expressed in Escherichia coli. The full-length PsGPx contained a 585-bp encoding 194 amino acids with predicted molecular masses of approx. 21.7 kDa. Multiple sequence alignments revealed that PsGPx belonged to the thioredoxin-like superfamily. PsGPx was heterologously overexpressed in E. coli, purified and characterized. The maximum catalytic temperature and pH value for recombinant PsGPx (rPsGPx) were 30°C and pH 9.0, respectively. rPsGPx retained 45% of the maximum activity at 0°C and exhibited high thermolability with a half-life of approx. 40 min at 40°C. In addition, the enzymatic activity of rPsGPx was still manifested under 3 M NaCl. The K and V values of the recombinant enzyme using GSH and HO as substrates were 1.73 mM and 16.28 nmol/mL/min versus 2.46 mM and 21.50 nmol/mL/min, respectively.
从南极嗜冷菌 Pseudoalteromonas sp. ANT506 中克隆了一种谷胱甘肽过氧化物酶 (GPx) 基因，命名为 PsGPx，并在大肠杆菌中表达。全长的 PsGPx 包含一个编码 194 个氨基酸的 585bp，预测分子量约为 21.7 kDa。多重序列比对表明，PsGPx 属于硫氧还蛋白超家族。PsGPx 在大肠杆菌中异源过表达、纯化和表征。重组 PsGPx(rPsGPx) 的最大催化温度和 pH 值分别为 30°C 和 pH 9.0。rPsGPx 在 0°C 时保留了最大活性的 45%，在 40°C 时半衰期约为 40 分钟，表现出很高的热不稳定性。此外，rPsGPx 在 3 M NaCl 下仍表现出酶活性。该重组酶以 GSH 和 HO 为底物时的 K 和 V 值分别为 1.73 mM 和 16.28 nmol/mL/min 与 2.46 mM 和 21.50 nmol/mL/min。
