Title of Paper:BIOCHEMICAL CHARACTERIZATION OF A NOVEL beta-N-ACETYLHEXOSAMINIDASE FROM THE INSECT OSTRINIA FURNACALIS

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Date of Publication:2013-07-01

Journal:ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY

Included Journals:SCIE、PubMed

Volume:83

Issue:3

Page Number:115-126

ISSN No.:0739-4462

Key Words:beta-N-acetylhexosaminidases; FDL; glycosylation; insect; N-glycan

Abstract:The -N-acetylhexosaminidase FDL specifically removes the -1,2-GlcNAc residue conjugated to the -1,3-mannose residue of the core structure of insect N-glycans, playing significant physiological roles in post-translational modification in the Golgi apparatus. Little is known about its enzymatic properties. We obtained the OfFDL gene from the insect Ostrinia furnacalis by RT-PCR. The full length cDNA of FDL is 2241 bp carrying an opening reading frame of 1923 bp encoding 640 amino acids. The recombinant protein OfFDL in a soluble and active form was obtained with high purity through a two-step purification strategy. The recombinant OfFDL exclusively hydrolyzes the terminal -1,2-GlcNAc residue from the -1,3 branch instead of the -1,6 branch of the substrate GnGn-PA. Several kinetic parameters including kcat/Km values toward four artificial substrates and Ki values of three representative hexosaminidase inhibitors were obtained. (C) 2013 Wiley Periodicals, Inc.