State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, PR China.
Carbohydr Polym. 2013 Jul 1;96(1):9-14. doi: 10.1016/j.carbpol.2013.03.061. Epub 2013 Mar 28.
D-Gal-6-sulfurylase catalyzing the conversion of μ-carrageenan into κ-carrageenan was extracted from Eucheuma striatum and purified by ammonium sulfate precipitation, hydrophobic interaction chromatography and ion exchange chromatography. The purified enzyme was a monomeric protein with a molecular mass of about 65 kDa as shown in SDS-PAGE. The maximum activity of the enzyme was observed at pH 7.0 and temperature 40°C. Km value for μ-carrageenan was 4.31 mM, and the corresponding Vmax was 0.17 mM min(-1). The carrageenan treated with 10 U of the purified enzyme exhibited 7.1-fold increase in gel strength with a removal of 30% sulfate groups. (1)H NMR spectral analysis of the control and enzyme treated carrageenan confirmed the conversion of μ- into κ-carrageenan and highlighted the specificity of Gal-6-sulfurylase for μ-carrageenan. This Gal-6-sulfurylase provides an eco-friendly and alternative for alkali treatment method to produce high gel strength κ-carrageenan.
从石花菜中提取并纯化了催化 μ-卡拉胶转化为 κ-卡拉胶的 D-半乳糖-6-硫酸酯酶，通过硫酸铵沉淀、疏水相互作用色谱和离子交换色谱进行纯化。纯化后的酶为单体蛋白，SDS-PAGE 显示其分子量约为 65 kDa。该酶的最适活性在 pH 7.0 和 40°C 下观察到。Km 值对于 μ-卡拉胶为 4.31 mM，相应的 Vmax 为 0.17 mM min(-1)。用 10 U 纯化的酶处理卡拉胶后，凝胶强度增加了 7.1 倍，硫酸基团去除率为 30%。对照和酶处理的卡拉胶的 (1)H NMR 光谱分析证实了 μ-卡拉胶向 κ-卡拉胶的转化，并强调了 Gal-6-硫酸酯酶对 μ-卡拉胶的特异性。这种 Gal-6-硫酸酯酶为生产高凝胶强度 κ-卡拉胶提供了一种环保且替代碱处理方法的选择。
