Bioresources Collection and Research Center, Food Industry Research and Development Institute, Number 331, Shih-Pin Road, Hsinchu 30062, Taiwan.
Institute of Food Science and Technology, National Taiwan University, Number 1, Section 4 Roosevelt Road, Taipei 10617, Taiwan.
J Food Drug Anal. 2018 Jan;26(1):163-171. doi: 10.1016/j.jfda.2016.12.016. Epub 2017 Feb 21.
Polygonum cuspidatum is a widely grown crop with a rich source of polydatin (also called piceid) for resveratrol production. Resveratrol is produced from piceid via enzymatic cleavage of the sugar moiety of piceid. In this study, Dekkera bruxellensis mutants were selected based on their high p-nitrophenyl-β-d-glucopyranoside and piceid conversion activities. The enzyme responsible for piceid conversion was a heterodimeric protein complex that was predominantly secreted to the extracellular medium and consisted of two subunits at an equal ratio with molecular masses of 30.5 kDa and 48.3 kDa. The two subunits were identified as SCW4p and glucan-β-glucosidase precursor in D. bruxellensis. Both proteins were individually expressed in Saccharomyces cerevisiae exg1Δ mutants, which lack extracellular β-glucosidase activity, to confirm each protein's enzymatic activities. Only the glucan-β-glucosidase precursor was shown to be a secretory protein with piceid deglycosylation activity. Our pilot experiments of piceid bioconversion demonstrate the possible industrial applications for this glucan-β-glucosidase precursor in the future.
虎杖是一种广泛种植的作物，其富含白藜芦醇生产的原儿茶酸（也称为白藜芦醇苷）。白藜芦醇是通过原儿茶酸的糖基部分的酶促裂解从白藜芦醇苷生产的。在这项研究中，根据其对 p-硝基苯-β-d-吡喃葡萄糖苷和白藜芦醇苷转化的高活性，选择了德克酵母突变体。负责白藜芦醇苷转化的酶是一种杂二聚体蛋白复合物，主要分泌到细胞外基质中，由两个亚基以相等的比例组成，分子量分别为 30.5 kDa 和 48.3 kDa。这两个亚基被鉴定为德克酵母中的 SCW4p 和葡聚糖-β-葡萄糖苷酶前体。这两种蛋白质分别在缺乏细胞外β-葡萄糖苷酶活性的酿酒酵母 exg1Δ 突变体中表达，以确认每种蛋白质的酶活性。只有葡聚糖-β-葡萄糖苷酶前体被证明是一种具有白藜芦醇苷去糖基化活性的分泌蛋白。我们对白藜芦醇苷生物转化的初步实验表明，这种葡聚糖-β-葡萄糖苷酶前体在未来可能具有工业应用价值。
