Dayler Charles S A, Mendes Paulo A M, Prates Maura V, Bloch Carlos, Franco Octavio L, Grossi-de-Sá Maria F
Embrapa Recursos Genéticos e Biotecnologia, Brasília, DF.
FEBS Lett. 2005 Oct 24;579(25):5616-20. doi: 10.1016/j.febslet.2005.09.030. Epub 2005 Sep 28.
Zabrotes subfasciatus is a devastating starch-dependent storage bean pest. In this study, we attempted to identify novel alpha-amylase inhibitors from wild bean seeds, with efficiency toward pest alpha-amylases. An inhibitor named Phaseolus vulgaris chitinolytic alpha-amylase inhibitor (PvCAI) was purified and mass spectrometry analyses showed a protein with 33330 Da with the ability to form dimers. Purified PvCAI showed significant inhibitory activity against larval Z. subfasciatus alpha-amylases with no activity against mammalian enzymes. N-terminal sequence analyses showed an unexpected high identity to plant chitinases from the glycoside hydrolase family 18. Furthermore, their chitinolytic activity was also detected. Our data provides compelling evidence that PvCAI also possessed chitinolytic activity, indicating the emergence of a novel alpha-amylase inhibitor class.
豆象是一种极具破坏性的依赖淀粉的贮藏豆类害虫。在本研究中，我们试图从野生豆类种子中鉴定出对害虫α-淀粉酶有效的新型α-淀粉酶抑制剂。一种名为菜豆几丁质分解性α-淀粉酶抑制剂（PvCAI）的抑制剂被纯化出来，质谱分析显示其为一种分子量为33330 Da的蛋白质，具有形成二聚体的能力。纯化后的PvCAI对豆象幼虫的α-淀粉酶具有显著抑制活性，而对哺乳动物酶无活性。N端序列分析表明，它与糖苷水解酶家族18中的植物几丁质酶具有意外的高度同源性。此外，还检测到了它们的几丁质分解活性。我们的数据提供了有力证据，表明PvCAI也具有几丁质分解活性，这表明出现了一种新型的α-淀粉酶抑制剂类别。
