超高压对α-CGTase产物专一性的影响

Effect of high pressure( HP) treatments on product specificity of α-CGTase

探讨了不同压力、不同温度对于α-CGTase产物专一性的影响,以及高压处理过后反应不同时间产物专一性的变化,确定了超高压作用于α-CGTase后环化反应产物专一性的变化规律。结果表明:在40℃,200 MPa下超高压不仅可显著提高α-CGTase产物专一性,同时保持较高酶活与产物得率。在40℃条件下,不同压力处理α-CGTase,随着压力升高,α-CGTase环化活力逐渐降低,反应产物专一性不断提高;在200 MPa下,不同温度处理α-CGTase,酶环化活力随温度升高而降低,产物专一性随温度升高先升高后降低;此外,高压处理α-CGTase后产物专一性随着反应时间的延长而降低。

Effects of different pressures （HP, 100 N 500 MPa） and different temperatures （25 -70℃ ） on prod- uct specificity of α-CGTase were studied. Results showed that the product specificity of α-CGTase increased a lot un- der 40℃ and 200MPa while enzyme activity and the product yield maintained very high. It was found that the product specificity of α-CGTase increased with the increase of pressures on α-CGTase at 40℃. When the pressure was under 200MPa, the cyclic activity of α-CGTase increased slightly with the increase of pressures, but it reduced rapidly if the pressure was above 200MPa. At the pressure of 200MPa, the cyclic activity was the highest （62.49U/mL） at 25℃ and the product specificity was the highest （55.9%） at 40℃. In addition, the product specificity of α-CGTase re- duced with the prolonged reaction time. Key words Cyclodextrin （CD） , α-Cyclodextrin glycosyltransferase （α-CGTase） , high pressure （ HP）, product specificity