Leshchinskaya I B, Shakirov E V, Itskovitch E L, Balaban N P, Mardanova A M, Sharipova M R, Viryasov M B, Rudenskaya G N, Stepanov V M
Department of Biology, Kazan State University, Russia.
FEBS Lett. 1997 Mar 10;404(2-3):241-4. doi: 10.1016/s0014-5793(97)00113-0.
A homogeneous glutamyl endopeptidase splitting peptide bonds of glutamic, rarely of aspartic acid residues in peptides and proteins, was isolated from Bacillus intermedius 3-19 culture filtrate using chromatography on CM cellulose and Mono S. The enzyme molecular mass is equal to 29 kDa, pI 8.4. The protease is inhibited by diisopropylfluorophosphate. The enzyme, like other glutamyl endopeptidases, reveals two pH optima at pH 7.5 and 9.0 for casein and one at pH 8.0 for Z-Glu-pNA hydrolysis. A 6 mM K(m) is found for hydrolysis of the latter substrate. The enzyme activity optimum lies at 55 degrees C, and it is stable at pH 6.5-11.0. Its N-terminal sequence shows 56% coinciding residues when compared with that of Bacillus licheniformis glutamyl endopeptidase.
从中间芽孢杆菌3-19培养滤液中，利用CM纤维素柱色谱和Mono S柱色谱分离出一种能切割肽和蛋白质中谷氨酸残基（很少切割天冬氨酸残基）肽键的均一谷氨酰内肽酶。该酶分子量为29 kDa，pI为8.4。该蛋白酶被二异丙基氟磷酸抑制。与其他谷氨酰内肽酶一样，该酶对酪蛋白在pH 7.5和9.0时显示两个最适pH值，对Z-谷氨酰-对硝基苯胺水解在pH 8.0时显示一个最适pH值。发现对后一种底物水解的K(m)为6 mM。该酶的最适活性温度为55℃，在pH 6.5 - 11.0范围内稳定。与地衣芽孢杆菌谷氨酰内肽酶相比，其N端序列显示有56%的相同残基。
