tailieunhanh - Báo cáo khoa học: A novel b-N-acetyl-D-hexosaminidase from the insect ´ Ostrinia furnacalis (Guenee)

Exploiting specific targets is of specific interest in developing eco-friendly pesticides. We isolated, purified and characterized a novel b-N-acetyl-d-hexosaminidase (OfHex1) from the fifth instar larva integument of the Asian corn borer,Ostrinia furnacalis(Guene´e). OfHex1 was purified 1468-fold to homogeneity with an activity yield of 20% by four column chroma-tography steps. | ễFEBS Journal A novel b-N-acetyl-D-hexosaminidase from the insect Ostrinia furnacalis Guenee Qing Yang1 Tian Liu1 Fengyi Liu1 Mingbo Qu1 and Xuhong Qian2 1 Department of Bioscience and Biotechnology Dalian University of Technology China 2 State Key Laboratory of Bioreactor Engineering East China University of Science and Technology China Keywords chitin glycosyl hydrolase pesticide target b-N-acetyl-D-hexosaminidase Correspondence Q. Yang Department of Bioscience and Biotechnology Dalian University of Technology 116024 Dalian Liaoning China Fax 86 411 84709687 Tel 86 411 84707245 E-mail qingyang@ Received 31 July 2008 revised 18 September 2008 accepted 19 September 2008 doi Exploiting specific targets is of specific interest in developing eco-friendly pesticides. We isolated purified and characterized a novel b-N-acetyl-D-hexosaminidase OfHex1 from the fifth instar larva integument of the Asian corn borer Ostrinia furnacalis Guenee . OfHexI was purified 1468fold to homogeneity with an activity yield of 20 by four column chromatography steps. Under denaturing conditions the molecular mass of OfHexl was determined to be kDa by MS and SDS PAGE but 128 kDa by gel filtration chromatography suggesting that it was in the form of a homodimer. Its pl was as determined by IEF electrophoresis. OfHex1 was shown to be an exo-splitting enzyme acting by cutting one b-GlcNAc unit once from the nonreducing ends of substrates with a preference for shorter substrates. OfHexl could hydrolyze p-nitrophenyl b-GlcNAc p-nitrophenyl b-GalNAc and chito-oligosaccharides degree of polymerization from 2 to 6 but it could not hydrolyze the complex N-gly-can substrate GlcNAcb-1 2Mana-1 6 GlcNAcb-1 2Mana-1 3 Manb-1 4GlcNAcb-1 4GlcNAc-PA as well as the long polymer chitin. Certain structural elements of substrates the 2-acetamido group and the b-glyco-side bond linkage were determined to be essential for its activity. The kb cDNA encoding .