کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1982648 1062305 2009 14 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Purification, characterization and sequencing of the major β-1,3-glucanase from the midgut of Tenebrio molitor larvae
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم کشاورزی و بیولوژیک دانش حشره شناسی
پیش نمایش صفحه اول مقاله
Purification, characterization and sequencing of the major β-1,3-glucanase from the midgut of Tenebrio molitor larvae
چکیده انگلیسی
The major β-1,3-glucanase from Tenebrio molitor (TLam) was purified to homogeneity (yield, 6%; enrichment, 113 fold; specific activity, 4.4 U/mg). TLam has a molecular weight of 50 kDa and a pH optimum of 6. It is an endoglucanase that hydrolyzes β-1,3-glucans as laminarin and yeast β-1,3-1,6-glucan, but is inactive toward other polysaccharides (as unbranched β-1,3-glucans or mixed β-1,3-1,4-glucan from cereals) or disaccharides. The enzyme is not inhibited by high substrate concentrations and has low processivity (0.6). TLam has two ionizable groups involved in catalysis, and His, Tyr and Arg residues plus a divalent ion at the active site. A Cys residue important for TLam activity is exposed after laminarin binding. The cDNA coding for this enzyme was cloned and sequenced. It belongs to glycoside hydrolase family 16, and is related to other insect glucanases and glucan-binding proteins. Sequence analysis and homology modeling allowed the identification of some residues (E174, E179, H204, Y304, R127 and R181) at the active site of the enzyme, which may be important for TLam activity. TLam efficiently lyses fungal cells, suggesting a role in making available walls and cell contents to digestion and in protecting the midgut from pathogen infections.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Insect Biochemistry and Molecular Biology - Volume 39, Issue 12, December 2009, Pages 861-874
نویسندگان
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