Suzuki Y, Hatagaki K, Oda H
Department of Agricultural Chemistry, Kyoto Prefectural University, Japan.
Appl Microbiol Biotechnol. 1991 Mar;34(6):707-14. doi: 10.1007/BF00169338.
A cell-associated pullulanase (alpha-dextrin 6-glucanohydrolase, EC 3.2.1.41) of an extreme thermophile, Bacillus flavocaldarius KP 1228, was purified to homogeneity. The molecular weight and isoelectric point were estimated to be about 55,000 and 7.0, respectively. The N-terminal sequence was Ala-Try-Tyr-Glu-Gly-Ala-Phe-Phe-Tyr-Gln-Ile-Phe-Pro-Asp-Tyr-Phe-Phe-Tyr- Ala- Gly-. The enzyme was most active at pH 6.3. The activities for 5% pullulan and 5% soluble starch were maximal at 75-80 degrees C and at 80-85 degrees C, respectively. The enzyme was stable up to 90 degrees C for 10 min at pH 6.8. The enzyme had no antigenic determinants shared with pullulanases from the mesophiles Klebsiella pneumoniae and B. acidopullulyticus NCIB 11647. A comparison of amino acid composition demonstrated that the proline content increased greatly in a linear fashion with the rise in thermostability in the order K. pneumoniae----B. acidopullulyticus----B. flavocaldarius enzymes, as found with Bacillus oligo-1,6-glucosidases.
一种嗜热栖热放线菌（Bacillus flavocaldarius）KP 1228的细胞相关支链淀粉酶（α-糊精6-葡聚糖水解酶，EC 3.2.1.41）被纯化至同质。其分子量和等电点估计分别约为55,000和7.0。N端序列为Ala-Try-Tyr-Glu-Gly-Ala-Phe-Phe-Tyr-Gln-Ile-Phe-Pro-Asp-Tyr-Phe-Phe-Tyr-Ala-Gly-。该酶在pH 6.3时活性最高。对于5%的支链淀粉和5%的可溶性淀粉，其活性分别在75 - 80℃和80 - 85℃时达到最大值。在pH 6.8时，该酶在高达90℃的温度下稳定10分钟。该酶与嗜温菌肺炎克雷伯菌和嗜酸解淀粉芽孢杆菌NCIB 11647的支链淀粉酶没有共同的抗原决定簇。氨基酸组成的比较表明，脯氨酸含量随着热稳定性的提高呈线性大幅增加，顺序为肺炎克雷伯菌----嗜酸解淀粉芽孢杆菌----嗜热栖热放线菌的酶，这与芽孢杆菌寡-1,6-葡萄糖苷酶的情况相同。
