BK21 Program, Department of Marine Science and Biotechnology, Inha University, Incheon 402-751, South Korea.
Appl Biochem Biotechnol. 2010 Sep;162(1):146-54. doi: 10.1007/s12010-009-8721-x. Epub 2009 Sep 27.
In this study, we attempted to purify and characterize glutaminase (EC. 3.5.1.2) from Lactobacillus reuteri KCTC3594. The glutaminase was purified approximately 21-fold from the cell-free extract of L. reuteri KCTC3594 by protamine sulfate treatment and chromatography methods including anion exchange and gel filtration. The sizes of two major bands of the enzyme were presumed to be 70 and 50 kDa by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The glutaminase activity of L. reuteri KCTC3594 was assayed in various ranges of pH, temperature, and salt concentrations. The enzyme activity was optimal at 40 degrees C and pH of 7.5. It was shown that the glutaminase was salt-tolerant because the enzyme activity was maintained 50% at 15% (w/v) salt concentrations. On the other hand, the enzyme was strongly inhibited up to 80% by 6-diazo-5-oxo-L-norleucine (10 mM) and iodoacetate (50 mM) indicating that the purified enzyme represents typical characteristics of glutaminase.
在这项研究中，我们试图从乳杆菌 KCTC3594 中纯化和鉴定谷氨酰胺酶（EC.3.5.1.2）。通过鱼精蛋白硫酸处理和包括阴离子交换和凝胶过滤在内的色谱方法，从乳杆菌 KCTC3594 的无细胞提取物中大约纯化了 21 倍的谷氨酰胺酶。通过十二烷基硫酸钠聚丙烯酰胺凝胶电泳，推测该酶的两个主要条带的大小分别为 70 和 50 kDa。在各种 pH 值、温度和盐浓度范围内测定了乳杆菌 KCTC3594 的谷氨酰胺酶活性。该酶在 40°C 和 pH 7.5 时活性最佳。结果表明，该酶具有耐盐性，因为在 15%（w/v）盐浓度下，酶活性保持在 50%。另一方面，该酶被 6-重氮-5-氧-L-正亮氨酸（10 mM）和碘乙酸（50 mM）强烈抑制，高达 80%，表明纯化的酶代表了谷氨酰胺酶的典型特征。
