Ogasawara W, Inanobe N, Ochiai K, Ando K, Okada H, Morikawa Y
Department of Bioengineering, Nagaoka University of Technology, Japan.
Biosci Biotechnol Biochem. 1997 Jan;61(1):146-51. doi: 10.1271/bbb.61.146.
We isolated a bacterial strain with an enzyme which releases dipeptide from Gly-Arg-p-nitroanilide. The bacterium was tentatively identified as Aureobacterium sp. The enzyme, named AuDAP, was purified and characterized. It was homogenous by SDS-PAGE and IEF, and had a molecular mass of 90,000 Da by SDS-PAGE and 88,000 Da by gel filtration, so it may be a monomer. The isoelectric point was 3.8 and the optimum pH was 10.0. The purified enzyme hydrolyzed Gly-Arg-pNA, a model substrate for DAP I, and Arg-Arg-MNA, a model substrate for DAP III. However, this enzyme did not hydrolyze Gly-Phe pNA, also a model substrate for DAP I. These results suggested that this enzyme did not fall under the classification of mammalian DAPs and was similar to DAP BI from Pseudomonas sp. WO24 and dDAP from Dictyostelium discoideum, although several differences were observed between them. The N-terminal amino acid sequence of this enzyme showed no significant homology to any enzyme and protein, except only for DAP BI.
我们分离出了一种带有能从甘氨酰-精氨酰-对硝基苯胺释放二肽的酶的细菌菌株。该细菌初步鉴定为金色杆菌属。这种名为AuDAP的酶被纯化并进行了特性分析。通过SDS-PAGE和IEF分析，它是纯一的，通过SDS-PAGE测得其分子量为90,000 Da，通过凝胶过滤测得为88,000 Da，所以它可能是单体。其等电点为3.8，最适pH为10.0。纯化后的酶能水解甘氨酰-精氨酰-对硝基苯胺（一种DAP I的模型底物）以及精氨酰-精氨酰-甲基萘胺（一种DAP III的模型底物）。然而，这种酶不能水解甘氨酰-苯丙氨酰-对硝基苯胺（同样是DAP I的一种模型底物）。这些结果表明，这种酶不属于哺乳动物DAPs的分类，并且与来自假单胞菌属WO24的DAP BI以及盘基网柄菌的dDAP相似，尽管它们之间存在一些差异。该酶的N端氨基酸序列与任何酶和蛋白质均无明显同源性，仅与DAP BI有同源性。
