Takahashi T, Kawauchi S, Suzuki K, Nakao E
Institute of Medicinal Chemistry, Hoshi University, Tokyo.
J Biochem. 1994 Dec;116(6):1251-6. doi: 10.1093/oxfordjournals.jbchem.a124671.
The effect of hydrostatic pressure on the bindability and digestibility of raw corn starch with two types of glucoamylase [EC 3.2.1.3] from Rhizopus sp., Gluc1 and Gluc2, was investigated in the range of 100 to 600 MPa. Pressurization of raw starch at 100 to 300 MPa for 1 h had no detectable effect, whereas pressurization at higher pressures than 400 MPa markedly enhanced the bindability and digestibility with Gluc1 and Gluc2, especially with Gluc2, which scarcely binds to raw starch and has much lower activity than Gluc1 towards raw starch. The binding constants Ks of Gluc1 and Gluc2 for the 400-MPa-pressurized starch reached 16 and 1.6 x 10(5) M-1, respectively, as compared with the Ks of 2.1 and 0.082 x 10(5) M-1 for raw starch. The 500- to 600-MPa-pressurized starch was digested by Gluc1 and Gluc2 at about 4.2 and 80 times higher rates, respectively, than raw starch. Thus, the high-pressure-treated starch was hardly distinguishable from high temperature (75 to 100 degrees C)-treated starch at least with respect to behavior with the enzymes, although some difference was observed between these starches by scanning electron microscopy and differential scanning calorimetry.
研究了在100至600兆帕范围内，静水压力对两种来自根霉属的葡糖淀粉酶[EC 3.2.1.3]（Gluc1和Gluc2）与生玉米淀粉的结合能力和消化率的影响。在100至300兆帕下对生淀粉加压1小时未检测到明显影响，而在高于400兆帕的压力下加压则显著增强了与Gluc1和Gluc2的结合能力和消化率，尤其是与Gluc2，它几乎不与生淀粉结合且对生淀粉的活性远低于Gluc1。对于400兆帕加压淀粉，Gluc1和Gluc2的结合常数Ks分别达到16和1.6×10⁵M⁻¹，而生淀粉的Ks分别为2.1和0.082×10⁵M⁻¹。500至600兆帕加压淀粉被Gluc1和Gluc2消化的速率分别比生淀粉高约4.2倍和80倍。因此，至少就酶的作用而言，高压处理淀粉与高温（75至100℃）处理淀粉几乎没有区别，尽管通过扫描电子显微镜和差示扫描量热法观察到这些淀粉之间存在一些差异。
