Tagatose is a rare hexoketose with potential health benefits. Here, an enzyme, GatZ subunit ofd-tagatose-1,6-bisphosphate aldolase, was characterized. GatZ is involved in a multi-enzyme cascade reaction system that can produce tagatose from maltodextrin. It showed maximum activity at 70 °C and a pH 8.0, and required supplementation with 5 mM Mg2+ to achieve the highest catalytic activity. The Km and Vmax values of GatZ using fructose 6-phosphate as substrate were 5.66 mM and 0.0329 mmol/L min, respectively. An in vitro multi-enzyme system containing GatZ was constructed, and 1.75 g/L tagatose was produced from 5 g/L maltodextrin after 10 h. This biosystem could potentially enrich the application of C4 epimerases in rare sugar bioproduction.

中文翻译：

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Caldilinea aerophila DSM 14535果糖6-磷酸4-差向异构酶的特性及其在塔格糖生物合成中的应用

塔格糖是一种罕见的己酮糖，具有潜在的健康益处。在这里，表征了一种酶，即 d-塔格糖-1,6-二磷酸醛缩酶的 GatZ 亚基。GatZ 参与了一个多酶级联反应系统，可以从麦芽糖糊精生产塔格糖。它在 70 °C 和 pH 8.0 时表现出最大活性，需要补充 5 mM Mg2+ 才能达到最高催化活性。使用果糖 6-磷酸作为底物的 GatZ 的 Km 和 Vmax 值分别为 5.66 mM 和 0.0329 mmol/L min。构建了含有GatZ的体外多酶系统，10 h后由5 g/L麦芽糊精生产1.75 g/L塔格糖。该生物系统可能会丰富 C4 差向异构酶在稀有糖生物生产中的应用。