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41.
To obtain a new serine protease from alkalophilic Bacillus sp. NKS-21, shotgun cloning was carried out. As a result, a new protease gene was obtained. It encoded an intracellular serine protease (ISP-1) in which there was no signal sequence. The molecular weight was 34,624. The protease showed about 50% homology with those of intracellular serine proteases (ISP-1) from Bacillus subtilis, B. polymyxa, and alkalophilic Bacillus sp. No. 221. The amino acid residues that form the catalytic triad, Ser, His and Asp, were completely conserved in comparison with subtilisins (the extracellular proteases from Bacillus). The cloned intracellular protease was expressed in Escherichia coli, and its purification and characterization were carried out. The enzyme showed stability under alkaline condition at pH 10 and tolerance to surfactants. The cloned ISP-1 digested well nucleoproteins, clupein and salmin, for the substrates.The nucleotide sequence data reported in this paper will appear in the GSDB, DDBJ, EMBL, and NCBI nucleotide sequence databases with the accession number D37921. 相似文献
42.
The effects of purified oxyleghaemoglobin components added toa suspension of bacteroids from soybean and pea root noduleprepared anaerobically were studied in terms of nitrogen fixationand oxygen consumption. Soybean leghaemoglobin components (Lba and Lb c) and pea leghaemoglobin components (Lb I and Lb IV)have different O2-binding affinities. Lb a and Lb IV showedhigher O2-binding affinities than Lb c and Lb I. When anaerobicallyprepared bacteroids were incubated with these leghaemoglobincomponents separately under low oxygen tension and in the presenceof a reduction system, Lb a and Lb IV were more effective forboth nitrogen fixation and oxygen consumption than Lb c andLb I. These results suggest that leghaemoglobin components participatein more effective nitrogen fixation by controlling oxygen transportto bacteroids. (Received July 7, 1981; Accepted November 2, 1981) 相似文献
43.
Acid-soluble collagens isolated from young and old rat tail tendon were fluorescent-labeled with dansyl hydrazine, which is capable of reacting with aldehyde groups in collagen. The dansyl fluorescence of aged collagen exhibited a weak peak at 525 nm, whereas that of young collagen had a stronger broad peak at 500 nm. Fibril formation in vitro was partially inhibited in these dansylated collagens. During the turbidity lag phase, the dansyl fluorescence was found to increase (30–50%), also shifting to 485 nm. These changes reveal the telopeptide conformation changes occurring during this period. A new fluorescence peak at 420 nm also increased during fibril formation. When the dansylated collagen was irradiated in air with uv light (340 nm), a rapid decrease of the dansyl fluorescence with a concurrent shift to 490 nm occurred. Also, the formation of fibrils was further inhibited. With increasing temperature, the dansyl fluorescence of young collagen decreased, whereas that of old collagen substantially increased, particularly at the denaturation temperature around 38°C. After denaturation, both fluorescences became similar in their intensity and position (490 nm). These findings are discussed in connection with both age-related structural changes of collagen and the mechanism of fibril formation. 相似文献
44.
Kohei Kawashima Eiji Watanabe Ken-ichi Isobe Michinori Ogura Ei-ichi Nagura Kazumasa Yamada Itsuro Sobue Kenji Mizoguchi Yasuhiko Ito Yoshiyuki Nagai Izumi Nakashima 《Cellular immunology》1982,67(2):279-286
During the course of immunization of (C3H × DBA/2)F1 mice (genotype H-2k/b) with L cell (H-2k/k)/L1210 leukemia cell (H-2d/d) hybrids and L1210 leukemia cells, some of them produced a good titer of anti-self-H-2 (H-2d) antibodies. Antigens recognized by this anti-self-H-2 antiserum were shown to be controlled by the H-2K-IA-IB-IJ-IE subregions of the H-2d but not H-2k nor H-2b haplotypes of parental as well as F1 origins and to have a tissue distribution identical to that of class 1 H-2 (H-2K/D) antigens. 相似文献
45.
Eiji Hara Tomoko Ohshima Takako Ishii Wataru Sugino Ko Tsutsui Susumu Nakada Nobuo Tsuchida Kinichiro Oda 《Experimental cell research》1992,198(2):250-258
The mechanism of induction of DNA synthesis in quiescent rat 3Y1 cells by the adenovirus E1A gene was investigated using the 3Y1 derivative cell lines g12-21, gn12RB1, and gn12RB2. The g12-21 cells express the E1A 12S cDNA and the latter two cells express both the E1A 12S cDNA and the human retinoblastoma susceptibility (Rb) gene at different levels in response to dexamethasone (dex). The cDNA sequences of E1A-inducible cell cycle-dependent genes, clone 3 and clone 16, were isolated by differential screening of a cDNA library constructed from dex-treated g12-21 cells. The quiescent 3Y1 cells induced c-fos and c-myc expression within 2 h after serum stimulation and expressed clone 16 and clone 3 transiently at around 8 h before the onset of DNA synthesis (10 h). In contrast, the quiescent g12-21 cells treated with dex expressed a high level of E1A at 6 to 8 h after treatment and expressed clone 16 and clone 3 at around 8 h without stimulation of c-fos and c-myc expression, suggesting that E1A bypasses the cell cycle early in G1. The half-maximal rate of DNA synthesis was reached in a much shorter time in dex-treated g12-21 cells (12 h) than in serum-treated 3Y1 cells (18 h), suggesting that E1A also bypasses the cell cycle at the G1/S boundary. The gn12RB1 and gn12RB2 cells were unable to induce DNA synthesis in response to dex presumably due to lower levels of E1A expression, although gn12RB2 but not gn12RB1 cells could express clone 16 and clone 3. These results suggest that the level of E1A required for bypass at the G1/S boundary is higher than that required early in G1. 相似文献
46.
Tetsuo Kunieda Eiji Kobayashi Hiroshi Ikadai Tomonori Imamichi Nobuo Nomura Ryotaro Ishizaki 《Biochemical genetics》1990,28(11-12):631-642
Novel restriction fragment length polymorphisms (RFLPs) in inbred rats were revealed with the human N-ras gene as probe. Three fragments hybridizing to the probe were detected by Southern blot hybridization under highly stringent conditions, and one of the fragments showed variation in inbred rat strains. Furthermore, on hybridization under low-stringency conditions, an additional fragment hybridizing to the probe was observed, and this fragment also showed interstrain variation. These two variant fragments showed different distributions in 27 inbred rat strains and segregated in backcross progeny as codominant alleles of independent single autosomal loci. Therefore, the loci for these RFLPs were named Nras-1 and Nras-2, respectively. Analyses of linkages between the RFLPs and 11 other loci revealed that the Nras-2 locus was closely linked to the c locus (3.7 +/- 2.6%), which belongs to rat linkage group I. 相似文献
47.
A new acid carboxypeptidase was purified fromAspergillus oryzae grown on solid bran culture medium. The purified enzyme was found to be homogeneous by disc gel electrophoresis at pH 9.4 and isoelectric focusing. The enzyme was termedA. oryzae acid carboxypeptidase O-1 with isoelectric point 4.08. The substrate specificity of the new enzyme was investigated with proangiotensin, angiotensin, and bradykinin. Even when the proline was present at the penultimate position of the peptide, the enzyme rapidly hydrolyzed the carboxyterminal Pro-X (X=amino acid) peptide bond. TheK
m
andk
cat
values for angiotension (–Pro7–Phe8) at pH 3.7 and 30°C were 0.2 mM and 1.7 sec–1, respectively. 相似文献
48.
49.
Protochlorophyll(ide) was isolated from dark-grown wild typeand mutant C-2A' cells of Scenedesmus obliquus after dark incubationwith 5-aminolevulinate. Proto-chlorophyll(ide) was detectedin mutant cells grown heterotrophically at 29°C or at 21°C.At the latter temperature chlorophyll synthesis was significant.Regulation of chlorophyll synthesis in algae is discussed.
1Present address: Laboratory of Chemistry, Faculty of Medicine,Teikyo University, Otsuka, Hachioji, Tokyo 192-03, Japan. (Received July 14, 1980; ) 相似文献
50.
Eiji Ichishima Yoshinori Tsuruda Taro Ushijima Takehiko Nomi Shoji Suzuki Michio Takeuchi Akiko Yamane 《Current microbiology》1980,4(2):85-89
The enzymological, physical, and immunological properties of soluble and bound forms of intracellular acid carboxypeptidase
isolated from fresh mycelia ofAspergillus saitoi are reported. In the broken mycelia, about 60% of the total activity was found in the 2,000×g precipitate, with most of the remainder in the 100,000×g supernantant. The highly purified enzymes, Ia and Ib, from the 100,000×g supernatant were found to be homogeneous by such criteria as disc gel electrophoresis at pH 9.4 The bound enzyme, II, was
solubilized from the 2,000×g precipitate by self-digestion at pH 6.4 and was highly purified by chromotography. The two forms of intracellular enzymes,
the soluble enzymes (Ia and Ib) from the 100,00×g supernatant and the solubilized enzyme (II) from the 2,000×g precipitate, were closely related to, but not completely identical with, the extracellular acid carboxypeptidase. 相似文献