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41.
Takashi Yamashita Naoto Tonouchi Takeshi Uozumi Teruhiko Beppu 《Molecular & general genetics : MGG》1987,210(3):462-467
Summary The aspartic protease gene of a zygomycete fungus Mucor pusillus was expressed in Saccharomyces cerevisiae under the control of the yeast GAL7 promoter. A putative preproenzyme with an NH2-terminal extension of 66 amino acids directed by the gene was processed in yeast cells and the mature enzyme, whose NH2-terminus was identical to that of the Mucor enzyme, was efficiently secreted into the medium at a concentration exceeding 150 mg/l. The enzyme secreted from the recombinant yeast was more glycosylated than the native Mucor enzyme but its enzymatic properties were almost identical with those of the native enzyme, which has been used as a milk coagulant in cheese manufacture. 相似文献
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Shosuke Ito Wolfram Gerwat Ludger Kolbe Toshiharu Yamashita Makoto Ojika Kazumasa Wakamatsu 《Pigment cell & melanoma research》2014,27(6):1149-1153
Racemic RS‐4‐(4‐hydroxyphenyl)‐2‐butanol (rhododendrol, RD) was used as a topical skin‐whitening agent until it was recently reported to induce leukoderma. We then showed that oxidation of RD with mushroom tyrosinase rapidly produces RD‐quinone, which is quickly converted to RD‐cyclic quinone and RD‐hydroxy‐p‐quinone. In this study, we examined whether either or both of the enantiomers of RD can be oxidized by human tyrosinase. Using a chiral HPLC column, racemic RD was resolved optically to R(?)‐RD and S(+)‐RD enantiomers. In the presence of a catalytic amount of l ‐dopa, human tyrosinase, which can oxidize l ‐tyrosine but not d ‐tyrosine, was found to oxidize both R(?)‐ and S(+)‐RD to give RD‐catechol and its oxidation products. S(+)‐RD was more effectively oxidized than l ‐tyrosine, while R(?)‐RD was less effective. These results support the notion that the melanocyte toxicity of RD depends on its tyrosinase‐catalyzed conversion to toxic quinones and the concomitant production of reactive oxygen species. 相似文献
44.
Mode of photosynthesis in Mesembryanthemum crystallinum changesfrom C3 to Crassulacean acid metabolism (CAM) when the plantswere stressed with high salinity. [14C]Pyruvate uptake for 30s into intact chloroplasts isolated from leaves of the CAM modeof M. crystallinum was enhanced more than 5-fold in the lightcompared with that in the dark. The stromal concentration ofpyruvate in the light reached to more than 2.5 times of themedium. In contrast, little or no pyruvate uptake occurred inchloroplasts from C3 leaves in either light or dark condition.The initial uptake rate (10 s incubation at 4°C) into theCAM chloroplasts in the light was about 3-fold higher than therate in the dark. Km and Vmax of the initial uptake in the lightwere 0.54 mM and 8.5 µmol (mg Chl)1 h1 respectively.These suggest that pyruvate was actively incorporated into theCAM chloroplasts against its concentration gradient across theenvelope in the light. When hydroponically grown M. crystallinumwere stressed by 350 mM NaCl, the capacity of chloroplasts forpyruvate uptake was induced in 6 d corresponding to the inductionof the activities of PEP-carboxylase and NAD(P)+-malic enzymesin response to salt stress. (Received October 12, 1995; Accepted January 19, 1996) 相似文献
45.
Poly(L-lysine) exists as a random-coil at neutral pH, an alpha-helix at alkaline pH, and a beta-sheet when the alpha-helix poly(L-lysine) is heated. The present Fourier-transform infrared (FTIR) study showed that short-chain alcohols (methanol, ethanol, and 2-propanol) partially transformed alpha-helix poly(L-lysine) to beta-sheet when their concentrations were low. At higher concentrations, however, these alcohols reversed the reaction, and the alcohol-induced beta-sheet was transformed back to alpha-helix structure. The reversal occurred at 1.40 M methanol, 0.96 M ethanol, and 0.55 M 2-propanol. The alcohol effects on the secondary structure were further investigated by circular dichroism (CD) on the thermally induced beta-sheet poly(L-lysine). Methanol, ethanol, and 1-propanol, but not 1-butanol, shifted the negative mean-residue ellipticity at 217 nm of the beta-sheet poly(L-lysine) to the positive side at low concentrations of the alcohols and to the negative side at high concentrations. With 1-butanol, only the positive-side shift was observed. The positive-side shift at low concentrations of alcohols indicates enhancement of the hydrophobic interactions among the side chains of the polypeptide in the beta-sheet conformation. The negative-side shift indicates a partial transformation to alpha-helix. The shift from the positive to negative side occurred at 7.1 M methanol, 4.6 M ethanol, and 3.1 M 1-propanol. The alcohol concentrations for the beta-to-alpha transition were higher in the CD study than in the IR study.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
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47.
Ke-Jing Wang Xiang-Hua Li Tetsuro Yamashita Yoshihito Takahata 《Plant Systematics and Evolution》2012,298(1):1-7
The wild soybean (Glycine soja), which is the progenitor of cultivated soybean (Glycine max), is expected to offer more information about genetic variability and more useful mutants for evolutionary research and breeding
applications. Here, a total of 1,600 wild soybean samples from China were investigated for genetic variation with regard to
the soybean Kunitz trypsin inhibitor (SKTI). A new mutant SKTI, Tik, was identified. It was found to be a Tia-derived codominant allele caused by a transversion point mutation from C to G at nucleotide +171, leading to an alteration
of one codon (AAC → AAG) and a corresponding amino acid substitution (Asn → Lys) at the ninth residue. Upon examination of
this variant and others previously found in wild soybeans, it became clear that SKTI has undergone high-level evolutionary
differentiation. There were more abundant polymorphisms in the wild than in the cultivated soybean. 相似文献
48.
Nobuhisa Ozaki Arigala Uma Ravi Sankar Mitsuji Yamashita Takashi Aoki Yasutaka Tanaka Motohiko Kimura Mitsuo Toda Michio Fujie Yasuo Takehara Harumi Sakahara 《Bioorganic & medicinal chemistry letters》2010,20(3):932-934
A new type of dendritic molecules Gd-DTPA-XDA-D1-Glc(OH), which work as a functionalized ligand coordinating gadolinium(III) ion at the center of their frameworks with two glucose moieties on the molecular surfaces, were readily synthesized with high yield. The structures were established by IR, 1H, 13C NMR, and mass spectral studies. Its bio-distribution patterns were evaluated on rats. 相似文献
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50.