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71.
S. Hayashi K. Matsuzaki Y. Takasaki H. Ueno K. Imada 《World journal of microbiology & biotechnology》1992,8(3):276-279
-Fructofuranosidase fromAspergillus japonicus, which produces 1-kestose (O--d-fructofuranosyl-(21)--d-fructofuranosyl -d-glucopyranoside) and nystose (O--d-fructofuranosyl-(21)--d-fructofuranosyl-(21)--d-fructofuranosyl -d-glucopyranoside) from sucrose, was purified to homogeneity by fractionation with calcium acetate and ammonium sulphate and chromatography with DEAE-Cellulofine and Sephadex G-200. Its molecular size was estimated to be about 304,000 Da by gel filtration. The enzyme was a glycoprotein which contained about 20% (w/w) carbohydrate. Optimum pH for the enzymatic reaction was 5.5 to 6. The enzyme was stable over a wide pH range, from pH 4 to 9. Optimum reaction temperature for the enzyme was 60 to 65°C and it was stable below 60°C. The Km value for sucrose was 0.21m. The enzyme was inhibited by metal ions, such as those of silver, lead and iron, and also byp-chloromercuribenzoate. 相似文献
72.
Sachio Hayashi Masaharu Nonoguchi Yoshihiko Shimokawa Yoshiyuki Takasaki Kiyohisa Imada 《Journal of industrial microbiology & biotechnology》1992,9(3-4):251-255
Summary Most of the carbohydrate moiety of -fructofuranosidaseP-1 fromAureobasidium sp. ATCC 20524 was removed by endo--N-acetylglucosaminidase F. A subunit of 94000 Da was observed in SDS-PAGE after deglycosylation. TheK
m value for sucrose was not changed by deglycosylation but the stability at pH 4–5 and 50°C was decreased. The deglycosylated enzyme was more sensitive to proteases such as pronase E and subtilisin than the native enzyme. It is considered that the carbohydrate moiety of -fructofuranosidaseP-1 contributes to the stability of the enzyme but is not essential in its catalytic function. 相似文献
73.
Neutral oligosaccharide structures linked to asparagines of porcine zona pellucida glycoproteins 总被引:2,自引:0,他引:2
N-Linked sugar chains were liberated by hydrazinolysis from porcine zona pellucida glycoproteins obtained from ovarian follicular oocytes. Neutral sugar chains were separated from acidic ones by paper electrophoresis and fractionated with a serial lectin column chromatography and Bio-Gel P-4 column chromatography. Their structural analysis by sequential glycosidase digestion in combination with methylation analysis revealed that the neutral sugar chains are of bi-, tri-, and tetraantennary complex type with a fucosylated trimannosyl core. Twenty-six percent of the sugar chains contain N-acetyllactosamine repeating structures in their outer chain moieties. Only linear N-acetyllactosamine repeats, the maximum size of which is hexasaccharide, are detected. A characteristic feature is that 39% of the sugar chains contain N-acetylglucosamine residues at their nonreducing termini in spite of the absence of bisected sugar chains. This study provided, for the first time, the substantial information about the sugar chain structures of mammalian zona pellucida glycoproteins. 相似文献
74.
Mauricio A. Lopes Koichi Takasaki Dwight E. Bostwick Tim Helentjaris Brian A. Larkins 《Molecular & general genetics : MGG》1995,247(5):603-613
Genetic modifiers of opaque2 convert the soft, starchy endosperm of opaque2 maize mutants to a hard, vitreous phenotype, while maintaining the enhanced lysine content of the grain. Genetic analysis of F2 segregating seeds from crosses of opaque2 by modified opaque2 genotypes indicated that the modifiers are complex traits that act codominantly. We developed two different segregating F2 populations and mapped the modifier loci by restriction fragment length polymorphism (RFLP) analysis. A relationship was found between formation of vitreous endosperm and the locus encoding the gamma-zein storage protein, which maps near the centromere of chromosome 7. Endosperm modification was consistently associated with the presence of two rather than one gamma-zein gene at this locus. A second modifier locus was mapped near the telomere of chromosome 7L. 相似文献
75.
Biopolymer flocculant produced by an Enterobacter sp. 总被引:11,自引:0,他引:11
Haruhiko Yokoi Takashi Yoshida Shingo Mori Jun Hirose Sachio Hayashi Yoshiyuki Takasaki 《Biotechnology letters》1997,19(6):569-573
A new biopolymer flocculant was produced by Enterobacter sp. BY-29. Flocculating activity increased in the presence of Al , Fe or Fe . The flocculant had flocculating activity not only in inorganic suspensions of kaolin and active carbon but also in organic suspensions of cellulose and yeast. The flocculant was an acidic polysaccharide consisting of glucose, galactose, xylose and galacturonic acid, and its MW was about 2.5 ¥ 10 6 Da. 相似文献
76.
Haruhiko Yokoi Michiko Shiraki Jun Hirose Sachio Hayashi Yoshiyuki Takasaki 《Biotechnology Techniques》1996,10(10):789-792
Summary Xanthan had a flocculating activity in a kaolin suspension and high flocculating activity was obtained in the suspension (pH 7.0) adding Al3+, Fe3+ or Fe2+. Xanthan had high flocculating activity not only in other inorganic suspensions such as active carbon and acid clay but also in organic suspensions of cellulose and yeast. From these flocculation properties, xanthan is anticipated to be utilized in wide areas as a new biodegradable, harmless biopolymer flocculant. 相似文献
77.
Yokoi Haruhiko Maeda Yukihide Hirose Jun Hayashi Sachio Takasaki Yoshiyuki 《Biotechnology Techniques》1997,11(6):431-433
Clostridium butyricum immobilized on porous glass beads in a column reactor evolved H 2 at 715 and 1,150 ml/l.h, with H 2 yields of 2.3 and 1.9 mol H 2 /mol glucose, at retention times of 2.0 and 1.0 h, respectively, with a medium containing 0.5 g glucose/l in continuous cultures without pH control. 相似文献
78.
The interaction of bovine thrombin [EC 3.4.21.5] with synthetic substrates and products was studied. The enzyme was purified from Parke-Davis topical thrombin. The purification process afforded some preparations with different clottin specific activities but with similar esterase specific activities. The preparation having highest clotting specific activity and that having lowest clotting activity were tentatively named thrombin-C and thrombin-E, respectively. Kinetic parameters for the hydrolysis of synthetic substrates and normality titrants were determined on the basis of active enzyme quantity, which was assayed by means of a fluorometric normality titrant. It was shown that thrombin-E was acylated by the substrates more slowly than thrombin-C, while deacylation proceeded at similar rates in the two preparations. The results were also compared with those obtained with bovine trypsin [EC 3.4.21.4]. The acylation rates of both thrombin preparations were markedly lower than that of trypsin, while the deacylation rates of the former were only slightly lower than that of the latter. The effects of various product-type inhibitors, such as benzyloxycarbonyl-, benzoyl-, and tosyl-L-arginine, were also examined. Thrombin was affected by these inhibitors not competitively, though trypsin was inhibited competitively. 相似文献
79.
Hiroyuki Takasaki Yukio Takahata Mariko Hiraiwa-Hasegawa Richard W. Byrne Takayoshi Kano 《Primates; journal of primatology》1986,27(4):517-519
A case of unusually early postpartum resumption of estrous cycling (<7 months) was recorded for a young, presumably primiparous
female in the M group of chimpanzees (Pan troglodytes schweinfurthii) in the Mahale Mountains National Park, western Tanzania. The female showed estrous cycling while lactating her infant, and
mated with young and low-ranking males as well as with the alpha male. 相似文献
80.
Adult rats were given large doses of MSG (4 g/kg) or isosmolar amounts of sodium chloride or L-alanine intraperitoneally or by forced intubation. Blood or plasma samples from these rats where assayed for osmolarity, hematocrit, pH, and concentrations of protein, sodium, potassium, chloride, calcium, magnesium, and urea nitrogen. Intraperitoneal MSG produced characteristic hypothalamic lesions; MSG by gavage failed to do so. Intraperitoneal MSG also caused major increases in plasma osmolarity, hemoconcentration, hypovolemia, alkalosis, hypernatremia, and uremia; plasma levels of chloride and potassium fell significantly. Administration of MSG by gavage caused much smaller changes in plasma osmolarity and sodium, and no significant changes in hematocrit, plasma protein or plasma urea nitrogen. Administration of sodium chloride or L-alanine (agents not known to produce the characteristics MSG brain lesions) caused some, but not all, of the metabolic changes seen after MSG. These observations suppot the hypothesis that the ability of large, concentrated doses of MSG to produce brain lesions in susceptible species involves a two-step process, i.e., initial damage to the blood-brain barrier for glutamate, followed by entry of the circulating amino acid into the extracellular space of the brain. 相似文献