Hanner M, Redl B, Stöffler G
Institute of Microbiology, Medical School, University of Innsbruck, Austria.
Biochim Biophys Acta. 1990 Feb 26;1033(2):148-53. doi: 10.1016/0304-4165(90)90005-h.
An intracellular aminopeptidase (EC 3.4.11.-) was purified from the extreme thermophilic archaebacterium, Sulfolobus solfataricus. The molecular weight of the native enzyme was about 320,000, as calculated by gel-filtration studies, and a subunit Mr of 80,000 was estimated by SDS-polyacrylamide gel electrophoresis. The temperature optimum of the enzyme was at 75 degrees C and the pH optimum was found to be 6.5. The aminopeptidase was highly active against the chromogenic substrates L-Leu-p-NA and L-Ala-p-NA. The enzyme was inhibited by EDTA, but the activity could be partially restored by removal of the EDTA and incubation with Co2+ or Mn2+. Bestatin, a typical inhibitor of aminopeptidase, fully inhibited the enzyme activity, but inhibitors of serine proteinases had no effect. Beside a high thermostability, the enzyme showed a remarkable stability against 6 M urea, organic solvents and acetonitrile.
从嗜热古细菌嗜热栖热菌（Sulfolobus solfataricus）中纯化出一种细胞内氨肽酶（EC 3.4.11.-）。通过凝胶过滤研究计算，天然酶的分子量约为320,000，通过SDS-聚丙烯酰胺凝胶电泳估计亚基分子量为80,000。该酶的最适温度为75℃，最适pH为6.5。该氨肽酶对生色底物L-亮氨酸-对硝基苯胺（L-Leu-p-NA）和L-丙氨酸-对硝基苯胺（L-Ala-p-NA）具有高活性。该酶受EDTA抑制，但通过去除EDTA并与Co2+或Mn2+孵育，活性可部分恢复。氨肽酶的典型抑制剂贝抑素（Bestatin）完全抑制酶活性，但丝氨酸蛋白酶抑制剂无作用。除了具有高耐热性外，该酶对6M尿素、有机溶剂和乙腈也表现出显著的稳定性。
