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31.
Induction and stimulation of 92-kDa gelatinase/type IV collagenase production in osteosarcoma and fibrosarcoma cell lines by tumor necrosis factor alpha 总被引:10,自引:0,他引:10
Y Okada H Tsuchiya H Shimizu K Tomita I Nakanishi H Sato M Seiki K Yamashita T Hayakawa 《Biochemical and biophysical research communications》1990,171(2):610-617
Production of a 92-kDa gelatinase/type IV collagenase and tissue inhibitor of metalloproteinases (TIMP) was investigated with human sarcoma cell lines. Among the cytokines and growth factors examined, only human recombinant tumor necrosis factor alpha (TNF alpha) induced and stimulated the proteinase with concomitant increase in TIMP expression, but matrix metalloproteinase 2 (72-kDa gelatinase/type IV collagenase) expression was unchanged. These data suggest that gene expression of the two metalloproteinases is regulated in a different fashion and TNF alpha may be important to allow cancer cells to be more invasive and metastatic. 相似文献
32.
Shinkichi Kamata Akira Okada Takehiko Watanabe Yasunaru Kawashima Hiroshi Wada 《Journal of neurochemistry》1980,35(5):1190-1199
The etiologic relationship between disturbances in metabolism of amino acids and amines and hepatic coma was investigated by examining the effects of diets containing various mixtures of amino acids on brain amine metabolism in rats with a portacaval shunt, using a method for simultaneous analysis of amino acids and amines. Rats with a portacaval shunt were fed on four different amino acid compositions with increased amounts of various amino acids suspected to be etiologically related to hepatic coma, such as methionine, phenylalanine, tyrosine, and tryptophan. The animals were killed 4 weeks after operation. During the experimental period, these animals did not become comatose, but exhibited various behavioral abnormalities. Marked increase in the plasma and brain levels of the augmented amino acids, especially methionine and tyrosine, were observed in rats with a portacaval shunt. Brain noradrenaline, dopamine, and serotonin levels were significantly decreased when the brain tyrosine level was increased. These results indicate that in rats with a portacaval shunt the dietary levels of amino acids greatly influence the brain levels of both amino acids and transmitter amines. 相似文献
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The substrate specificity of spermidine dehydrogenase from Serratia marcescens was studied using many kinds of naturally occurring and synthetic polyamines. Diamines inhibited the enzyme competitively and their inhibitor constants tended to decrease with increasing methylene chain length in the diamines. All of the triamines and tetramines examined were active as substrates, and the amines containing a 4-aminobutylimino moiety (NH2(CH2)4NH-) in their structures were more active. N-Alkylputrescine was also oxidized by the enzyme. All of the amines containing a 4-aminobutylimino group were oxidized to form 1-pyrroline stoichiometrically as one of the products. Tetramines containing a 3-aminopropylimino group (NH2(CH2)3NH-) were oxidized to form 1,3-diaminopropane. However, in the case of an amine containing both 4-aminobutylimino and 3-aminopropylimino groups, the imino moiety of the former was preferentially oxidized by the enzyme. On the basis of the substrate specificity, the binding characteristics of the enzyme are discussed and a subsite model for the binding site is proposed. 相似文献
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Shin-ya Tanimoto Michiko Yamashita Soichi Arai Masao Fujimaki 《Bioscience, biotechnology, and biochemistry》2013,77(9):1595-1602
A plastein was synthesized with α-chymotrypsin from a dialyzable fraction of a peptic hydrolysate of soybean protein.The plastein was obtainable also by use of an insoluble preparation of α-chymotrypsin. This may rule out the possibility that the plastein is a product resulting from some chemical peptide-protein (enzyme) aggregation.No appreciable amount of the plastein was produced when chymotrypsinogen was used instead of α-chymotrypsin.The plastein synthetic, as well as the protein hydrolytic, activity of α-chymotrypsin was inhibited more or less by a hydrophobic inhibitor (n-hexane), a competitive inhibitor (benzolyl-d,l-phenylalanine), and divalent cations (Zn2+, Hg2+ and Cu2+); the degree of inhibition in each case was approximately similar against both the synthetic and the hydrolytic activities.Either diisopropylphosphorylation of the β-O of Ser-195 or methylation of the 3-N of His-57 imidazole of α-chymotrypsin repressed the synthetic, as well as the hydrolytic, activity.Based on these results a possible mechanism was discussed of the plastein synthesis by α-chymotrypsin, especially in relevance to its acylation and deacylation. 相似文献
40.
Retropositional parasitism of SINEs on LINEs: identification of SINEs and LINEs in elasmobranchs. 总被引:4,自引:0,他引:4
Some previously unidentified short interspersed repetitive elements (SINEs) and long interspersed repetitive element (LINEs) were isolated from various higher elasmobranchs (sharks, skates, and rays) and characterized. These SINEs, members of the HE1 SINE family, were tRNA-derived and were widespread in higher elasmobranches. The 3'-tail region of this SINE family was strongly conserved among elasmobranchs. The LINEs, members of the HER1 LINE family, encoded an amino acid sequence similar to that encoded by the chicken CR1 LINE family, and they contained a strongly conserved 3'-tail region in the 3' untranslated region. This tail region of the HER1 LINE family was almost identical to that of the HE1 SINE family. Thus, the HE1 SINE family and the HER1 LINE family provide a clear example of a pair of SINEs and LINEs that share the same tail region. Conservation of the secondary structures of the tail regions, as well as of the nucleotide sequences, between the HE1 SINE family and HER1 LINE family during evolution suggests that SINEs utilize the enzymatic machinery for retroposition of LINEs through the recognition of higher-order structures of the conserved 3'-tail region. A discussion is presented of the parasitism of SINEs on LINEs during the evolution of these retroposons. 相似文献