Crespim Elaine, Zanphorlin Letícia M, de Souza Flavio H M, Diogo José A, Gazolla Alex C, Machado Carla B, Figueiredo Fernanda, Sousa Amanda S, Nóbrega Felipe, Pellizari Vivian H, Murakami Mário T, Ruller Roberto
Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192, CEP 13083-970, Campinas, São Paulo, Brasil.
Laboratório Nacional de Biociências (LNBio), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192, CEP 13083-970, Campinas, São Paulo, Brasil.
Int J Biol Macromol. 2016 Jan;82:375-80. doi: 10.1016/j.ijbiomac.2015.09.018. Epub 2015 Oct 22.
A novel GH1 β-glucosidase (EaBgl1A) from a bacterium isolated from Antarctica soil samples was recombinantly overexpressed in Escherichia coli cells and characterized. The enzyme showed unusual pH dependence with maximum activity at neutral pH and retention of high catalytic activity in the pH range 6 to 9, indicating a catalytic machinery compatible with alkaline conditions. EaBgl1A is also a cold-adapted enzyme, exhibiting activity in the temperature range from 10 to 40°C with optimal activity at 30°C, which allows its application in industrial processes using low temperatures. Kinetic characterization revealed an enzymatic turnover (Kcat) of 6.92s(-1) (cellobiose) and 32.98s(-1) (pNPG) and a high tolerance for product inhibition, which is an extremely desirable feature for biotechnological purposes. Interestingly, the enzyme was stimulated by up to 200 mM glucose, whereas the commercial cocktails tested were found fully inhibited at this concentration. These properties indicate EaBgl1A as a promising biocatalyst for biotechnological applications where low temperatures are required.
从南极土壤样本中分离出的一种细菌的新型GH1β-葡萄糖苷酶（EaBgl1A）在大肠杆菌细胞中进行了重组过表达并进行了特性分析。该酶表现出不同寻常的pH依赖性，在中性pH下具有最大活性，并且在6至9的pH范围内保持高催化活性，表明其催化机制与碱性条件兼容。EaBgl1A也是一种冷适应酶，在10至40°C的温度范围内具有活性，在30°C时具有最佳活性，这使其能够应用于低温工业过程。动力学特性显示其酶促周转率（Kcat）为6.92s⁻¹（纤维二糖）和32.98s⁻¹（对硝基苯-β-D-葡萄糖苷），并且对产物抑制具有高耐受性，这是生物技术应用中极为理想的特性。有趣的是，该酶受到高达200 mM葡萄糖的刺激，而测试的商业混合物在此浓度下被完全抑制。这些特性表明EaBgl1A是一种有前途的生物催化剂，可用于需要低温的生物技术应用。
