title: Comparative characterization of chitinases from silkworm (Bombyx mori) and bollworm (Helicoverpa armigera).
abstract: Chitinases play an important role in the degradation of the cuticular chitin during the process of ecdysis. In this study, we compared the chitinases of two insect species, Bombyx mori (silkworm) and Helicoverpa armigera (bollworm), to assess the relation between characteristics and chitinase patterns. Differences between two chitinases were observed after purification using ammonium sulfate precipitation, affinity chromatography, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) assay. Although the specific activities of the purified enzymes were different, the purification yields were similar. One band of 88 kDa was observed for B. mori, and the other band of 75 kDa was detected for H. armigera. When a range of properties was tested, it was found that the optimum temperatures of B. mori and H. armigera chitinases were 45 and 50°C, respectively; the optimum pH value was 6.0 for both chitinases. Mn(2+) played catalytic role while Cu(2+) and SDS strongly inhibited activities of both enzymes. Between two chitinases, differences in K (M) were also observed. K (M) of chitinase from silkworm and bollworm was found to be 22.3 and 41.0 μmol/l, respectively. Both the chitinases significantly inhibited the spore germination of two fungal species, Saccharomyces cerevisiae and Penicillium.
authors.affiliation: Department of Pharmaceutical Engineering, Hefei University of Technology, Hefei, China. hbzhang@hfut.edu.cn
authors.forename: HongBin
authors.initials: H
authors.lastname: Zhang
authors.forename: MingYan
authors.initials: M
authors.lastname: Liu
authors.forename: YuJing
authors.initials: Y
authors.lastname: Tian
authors.forename: XueQin
authors.initials: X
authors.lastname: Hu
mesh_terms: D000645:Ammonium Sulfate / Q000737:chemistry; D000818:Animals; D000935:Antifungal Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism* / Q000494:pharmacology; D012831:Bombyx / Q000201:enzymology*; D011232:Chemical Precipitation; D002688:Chitinases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism* / Q000494:pharmacology; D002845:Chromatography; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents / Q000494:pharmacology; D007700:Kinetics; D008670:Metals / Q000494:pharmacology; D010407:Penicillium / Q000187:drug effects / Q000254:growth & development; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000254:growth & development; D013045:Species Specificity; D013172:Spores, Fungal / Q000187:drug effects / Q000254:growth & development; D013696:Temperature
chemical_list: D000935:Antifungal Agents; D007202:Indicators and Reagents; D008670:Metals; D002688:Chitinases; D000645:Ammonium Sulfate