A novel thermostable extracellular chitinase was purified from the culture filtrate of Thermomyces lanuginosus SY2 by using diethylaminoethyl Sepharose chromatography and Phenyl-Sepharose chromatography. The molecular...A novel thermostable extracellular chitinase was purified from the culture filtrate of Thermomyces lanuginosus SY2 by using diethylaminoethyl Sepharose chromatography and Phenyl-Sepharose chromatography. The molecular size of the purified chitinase was estimated to be 48 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The chitinase exhibited optimum catalytic activity at pH 4.5 and 55℃. The enzyme was stable at 50℃, and its half-life time at 65℃ was 25 rain. The thermostable chitinase was obtained with 60% of the full activity, when it was incubated in the buffer （pH 2.5）. The enzyme showed the unique properties for thermostability and pH stability since it was one of the most thermostable chitinases so far isolated in fungi. Ca^2＋, Ba^2＋, Na^＋, and K^＋ enhanced the enzyme activity, whereas Fe^2＋, Ag^＋, Hg^2＋, and ethylene diamine tetraacetic acid caused obvious inhibition. The N-terminal amino acids were AQGYLSVQYFVNWAI. Degenerate primers based on the N-terminal sequences of purified chitinase and a cDNA fragment encoding the chitinase gene were obtained through reverse transcriptase-polymerase chain reaction amplication. The RACE was used to generate full-length cDNA clones. The cDNA of chit contained an open reading frame of 1 326 bp encoding 442 amino acids. The gene chit has been registered in GenBank with accession number DQ092332. The alignment results of putative amino acid sequence showed the lower similarity to other chitinases in family-18 except for the catalytic domain containing two conserved motifs related with catalytic activity of chitinase.展开更多
By using the group IIIB or groupVIIB metals and modulating thecharacteristics of electric charges on carrier surface, improving the catalyst preparation processand techniques for loading the active metal components, a...By using the group IIIB or groupVIIB metals and modulating thecharacteristics of electric charges on carrier surface, improving the catalyst preparation processand techniques for loading the active metal components, a novel type SY-2 catalyst earmarked fortwo-stage hydrogenation of pyrolysis gasoline has been developed. The catalyst evaluation resultshave indicated that the novel catalyst is characterized by a better hydrogenation reaction activityto give higher aromatic yield.展开更多
基金the Science Technology Plan Foundation of Hebei Province, China (07225533)the Doctor Foundation from Agricultural University of Hebei (050031)
文摘A novel thermostable extracellular chitinase was purified from the culture filtrate of Thermomyces lanuginosus SY2 by using diethylaminoethyl Sepharose chromatography and Phenyl-Sepharose chromatography. The molecular size of the purified chitinase was estimated to be 48 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The chitinase exhibited optimum catalytic activity at pH 4.5 and 55℃. The enzyme was stable at 50℃, and its half-life time at 65℃ was 25 rain. The thermostable chitinase was obtained with 60% of the full activity, when it was incubated in the buffer （pH 2.5）. The enzyme showed the unique properties for thermostability and pH stability since it was one of the most thermostable chitinases so far isolated in fungi. Ca^2＋, Ba^2＋, Na^＋, and K^＋ enhanced the enzyme activity, whereas Fe^2＋, Ag^＋, Hg^2＋, and ethylene diamine tetraacetic acid caused obvious inhibition. The N-terminal amino acids were AQGYLSVQYFVNWAI. Degenerate primers based on the N-terminal sequences of purified chitinase and a cDNA fragment encoding the chitinase gene were obtained through reverse transcriptase-polymerase chain reaction amplication. The RACE was used to generate full-length cDNA clones. The cDNA of chit contained an open reading frame of 1 326 bp encoding 442 amino acids. The gene chit has been registered in GenBank with accession number DQ092332. The alignment results of putative amino acid sequence showed the lower similarity to other chitinases in family-18 except for the catalytic domain containing two conserved motifs related with catalytic activity of chitinase.
文摘By using the group IIIB or groupVIIB metals and modulating thecharacteristics of electric charges on carrier surface, improving the catalyst preparation processand techniques for loading the active metal components, a novel type SY-2 catalyst earmarked fortwo-stage hydrogenation of pyrolysis gasoline has been developed. The catalyst evaluation resultshave indicated that the novel catalyst is characterized by a better hydrogenation reaction activityto give higher aromatic yield.
