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排序方式: 共有1014条查询结果,搜索用时 15 毫秒
1.
K Nakashima T Tsukada H Hibasami S Maekawa 《Biochemical and biophysical research communications》1986,141(2):718-722
N-Chlorosulfonyl dicyclohexylamine (CSD) was synthesized as a potent inhibitor of spermidine synthase and analyzed for antiproliferative effects on leukemic cells. The compound specifically inhibited spermidine synthase in a competitive mode with the substrate putrescine (Ki, 1.8 X 10(-7) M). When human leukemia Molt4B cells were cultured in the presence of the inhibitor, the intracellular level of spermidine and the rate of cell proliferation were markedly depressed. In these polyamine depleted and growth retarded cells the synthesis of protein, but not of DNA or RNA, was found to be significantly diminished. 相似文献
2.
3.
M Nakamura M Oda K Kaneko Y Yonei N Tsukada H Komatsu M Tsugu M Tsuchiya 《Peptides》1987,8(2):391-398
The location of 125I-iodotyrosyl gastrin I binding sites in rat gastric mucosa was studied. Peptide specificity was demonstrated by competitive binding studies through the addition of a large dose of cold human gastrin I or cholecystokinin-octapeptide. Autoradiography of the stomach tissue was carried out by freeze-drying, embedding in Epon, wet-sectioning with ethylene glycol, and dry-mounting the emulsion film by means of the wire-loop method to prevent loss of the labeled substance. Specific binding sites for gastrin were found on parietal and chief cells, whereas few binding sites were seen on the surface mucous or mucous neck cells. Binding sites on the parietal cells were dispersed in the cytoplasm, while those on the chief cells were found near the basal plasma membrane. 相似文献
4.
H Hibasami T Tsukada S Maekawa M Sakurai K Nakashima 《Biochemical and biophysical research communications》1987,144(2):757-762
Ornithine decarboxylase (ODC) was induced in the liver, lung and brain of the mouse injected intraperitoneally with 12-O-tetradecanoylphorbol 13-acetate (TPA), showing maximal enzyme activity four hours after the injection. The increase of ODC activity was due to the enhanced syntheses of mRNA and protein. The induction of ODC activity by TPA was specifically blocked by methylglyoxal bis(butylamidinohydrazone) (MGBB), a competitive inhibitor of ODC and S-adenosylmethionine decarboxylase, but not by the analog methylglyoxal bis(guanylhydrazone) (MGBG). 相似文献
5.
The nuclear matrix from rat liver is capable of phosphorylating exogenous tyrosine-containing substrates 总被引:1,自引:0,他引:1
The nuclear matrix isolated from rat liver phosphorylated exogenous tyrosine-containing substrates angiotensin II and synthetic polymer (Glu, Tyr; 4:1). The phosphorylation reaction was dependent on Mn2+ or Mg2+, but the former was the preferred ion. Km values for poly(Glu,Tyr; 4:1) and ATP were 0.2 mM and 4 microM, respectively. Angiotensin II showed a lower affinity for the kinase than poly(Glu,Tyr; 4:1). The isoflavone genistein, a specific inhibitor for tyrosine phosphorylation, inhibited the tyrosine kinase activity in the nuclear matrix. 相似文献
6.
7.
Kato Yoji; Otsuki Tatsuya; Nakajima Tasuku; Ojima Kunihiko; Matsuda Kazuo 《Plant & cell physiology》1988,29(4):539-547
-Glucans (average mol wt, 1.3 ? 104) extracted with perchloricacid from 8-day-old suspension-cultured nonglutinous (var. Sasanishiki)and glutinous rice (var. Miyakogane) cells were compared. Theresults of hydrolysis by alpha;-, ß- and iso-amylasesand methylation analysis of the -glucans suggested that theirbasic structures are almost the same. These -glucans are highly-branchedpolysaccharides with an average chain length of about 910,with exterior and interior chain lengths of about 67and 23, respectively.
1Current address: Laboratory of Food Science, Faculty of Education,Hirosaki University, Hirosaki, Aomori 036, Japan. (Received April 27, 1987; Accepted March 2, 1988) 相似文献
8.
Complete purification and immunochemical analysis of S-adenosylmethionine synthetase from bovine brain 总被引:4,自引:0,他引:4
We have purified S-adenosylmethionine (AdoMet) synthetase about 3000-fold from bovine brain extract. The Km values of the enzyme for L-methionine and ATP were 10 and 50 microM, respectively. An apparent molecular mass of the enzyme was estimated to be 160 kDa by gel filtration on a Sephacryl S-200 column. Sucrose density gradient centrifugation gave a sedimentation coefficient of 8 S. Polyacrylamide gel electrophoresis of the purified enzyme in native system revealed a single protein band, whereas two polypeptide bands with molecular masses of 48 kDa (p48) and 38 kDa (p38) were observed in sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified enzyme. Antibody against bovine brain AdoMet synthetase was prepared by injecting the purified enzyme into a rabbit. Immunoblot analysis revealed that the antibody recognized both p48 and p38 in the impure enzyme preparations from bovine brain as well as in the purified enzyme. Specific antibodies against p48 and p38 were separated from the immunoglobulin fraction by an affinity purification, both of which inhibited the enzyme activity. These results indicate that AdoMet synthetase from bovine brain consists of two different polypeptides, p48 and p38. 相似文献
9.
Expression of adrenocorticotropin-releasing hormone precursor gene in placenta and other nonhypothalamic tissues in man 总被引:1,自引:0,他引:1
T Usui Y Nakai T Tsukada H Jingami H Takahashi J Fukata H Imura 《Molecular endocrinology (Baltimore, Md.)》1988,2(9):871-875
Adrenocorticotropin-releasing hormone (CRH) is a peptide originally isolated from the hypothalamus. Immunocytochemical and RIA studies have revealed that CRH-like peptide is also localized in human nonhypothalamic tissues and some tumors. To see if CRH is synthesized in these nonhypothalamic tissues and tumors, we examined preproCRH mRNA in these tissues by Northern blot analysis using a cloned human preproCRH gene as a probe. PreproCRH mRNA was detected in human hypothalamus, cerebral cortex, adrenal gland, placenta, pheochromocytoma, and thymic carcinoid. The content of preproCRH mRNA in placenta was apparently greater than that in the whole hypothalamus. 相似文献
10.
Spermidine synthase from rat ventral prostate was inhibited by 2-mercaptoethylamine (MEA). Inhibition of spermidine synthase by MEA was competitive with respect to one of the substrates putrescine, but not competitive with respect to the other substrate decarboxylated S-adenosylmethionine. MEA markedly depressed spermidine and spermine contents in human erythroid leukemia K562 cells, suggesting that these changes resulted from the inhibitory effect of MEA on spermidine synthase in situ. 相似文献