Tanaka Yuki, Matsumura Kanon, Ariga Miyu, Konno Naotake, Ogata Makoto, Habu Naoto
1 Faculty of Food and Agricultural Sciences, Fukushima University.
3 Graduate School of Regional Development and Creativity, Utsunomiya University.
J Appl Glycosci (1999). 2025 Aug 20;72(3):7203102. doi: 10.5458/jag.7203102. eCollection 2025.
Cellouronate, β-1,4-glucuronan, is synthesized from regenerated cellulose via 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) radical-mediated oxidation. Human intestinal bacteria were cultured in a medium containing cellouronate to evaluate its utilization. These experiments showed to grow well in this medium. Several putative cellouronate lyases belonging to polysaccharide lyase family 38 from were identified. Among these candidate enzymes, CUL1, which displayed the most similarity to authentic cellouronate lyases, was heterologously expressed and characterized. The recombinant CUL1 (rCUL1) showed the highest activity at pH 8.0 and was deactivated by treatment at pH 3.0 for 24 h or heating above 50 °C for 10 min. Moreover, the activity of rCUL1 was enhanced in the presence of Mg, Ca, or EDTA, but suppressed by Al and completely inactivated by Fe. Analysis of the final reaction mixture generated from the rCUL1 mediated degradation of cellouronate revealed an oligomer as the main product, but the monomer was barely detectable. This study is the first to report and characterize a cellouronate lyase from human intestinal bacteria.
β-1,4-葡糖醛酸聚糖是通过2,2,6,6-四甲基哌啶-1-氧基（TEMPO）自由基介导的氧化反应由再生纤维素合成的。将人类肠道细菌在含有β-1,4-葡糖醛酸聚糖的培养基中培养，以评估其利用情况。这些实验表明细菌在该培养基中生长良好。从[具体来源未给出]中鉴定出了几种属于多糖裂解酶家族38的假定β-1,4-葡糖醛酸聚糖裂解酶。在这些候选酶中，与正宗β-1,4-葡糖醛酸聚糖裂解酶相似度最高的CUL1被异源表达并进行了表征。重组CUL1（rCUL1）在pH 8.0时表现出最高活性，在pH 3.0处理24小时或在50℃以上加热10分钟会使其失活。此外，rCUL1的活性在Mg、Ca或EDTA存在时增强，但被Al抑制，被Fe完全灭活。对rCUL1介导的β-1,4-葡糖醛酸聚糖降解产生的最终反应混合物的分析表明，主要产物是一种低聚物，但几乎检测不到单体。本研究首次报道并表征了一种来自人类肠道细菌的β-1,4-葡糖醛酸聚糖裂解酶。
