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911.
Furusato M Sueyoshi N Mitsutake S Sakaguchi K Kita K Okino N Ichinose S Omori A Ito M 《The Journal of biological chemistry》2002,277(19):17300-17307
Recently, lyso-sphingolipids have been identified as ligands for several orphan G protein-coupled receptors, although the molecular mechanism for their generation has yet to be clarified. Here, we report the molecular cloning of the enzyme, which catalyzes the generation of lyso-sphingolipids from various sphingolipids (sphingolipid ceramide N-deacylase). The 75-kDa enzyme was purified from the marine bacterium, Shewanella alga G8, and its gene was cloned from a G8 genomic library using sequences of the purified enzyme. The cloned enzyme was composed of 992 amino acids, including a signal sequence of 35 residues, and its molecular weight was estimated to be 109,843. Significant sequence similarities were found with an unknown protein of Streptomyces fradiae Y59 and a Lumbricus terrestris lectin but not other known functional proteins. The 106-kDa recombinant enzyme expressed in Escherichia coli hydrolyzed various glycosphingolipids and sphingomyelin, although it seems to be much less active than the native 75-kDa enzyme. In vitro translation using wheat germ extract revealed the activity of a 75-kDa deletion mutant lacking a C terminus to be much stronger than that of the full-length enzyme, suggesting that C-terminal processing is necessary for full activity. 相似文献
912.
913.
Kakiuchi M Okino N Sueyoshi N Ichinose S Omori A Kawabata S Yamaguchi K Ito M 《Glycobiology》2002,12(2):85-94
We report here the purification, characterization, and cDNA cloning of a novel N-acetylgalactosamine-specific lectin from starfish, Asterina pectinifera. The purified lectin showed 19-kDa, 41-kDa, and 60-kDa protein bands on SDS-PAGE, possibly corresponding to a monomer, homodimer, and homotrimer. Interestingly, on 4-20% native PAGE the lectin showed at least nine protein bands, among which oligomers containing six to nine subunits had potent hemagglutination activity for sheep erythrocytes. The hemagglutination activity of the lectin was specifically inhibited by N-acetylgalactosamine, Tn antigen, and blood group A trisaccharide, but not by N-acetylglucosamine, galactose, galactosamine, or blood group B trisaccharide. The specificity of the lectin was further examined using various glycosphingolipids and biotin-labeled lectin. The lectin was found to bind to Gb5Cer, but not Gb4Cer, Gb3Cer, GM1a, GM2, or asialo-GM2, indicating that the lectin specifically binds to the terminal alpha-GalNAc at the nonreducing end. The hemagglutination activity of the lectin was completely abolished by chelation with EDTA or EGTA and completely restored by the addition of CaCl(2). cDNA cloning of the lectin showed that the protein is composed of 168 amino acids, including a signal sequence of 18 residues, and possesses the typical C-type lectin motif. These findings indicate that the protein is a C-type lectin. The recombinant lectin, produced in a soluble form by Escherichia coli, showed binding activity for asialomucin in the presence of Ca(2+) but no hemagglutination. 相似文献
914.
915.
Localization of prostatic basic protein ("probasin") in the rat prostates by use of monoclonal antibody 总被引:2,自引:0,他引:2
Y Matuo N Nishi Y Muguruma Y Yoshitake N Kurata F Wada 《Biochemical and biophysical research communications》1985,130(1):293-300
Isolated nuclei of the rat prostates contain a unique androgen-dependent basic protein, "probasin". Despite that it was hardly detectable in the cytosol centrifugally prepared from the prostates, immunofluorescent histological analysis of whole tissues using monoclonal antibody, which was raised against probasin purified from the nuclei, revealed that probasin was abundantly localized in the lumen and acinal regions of the epithelium, but hardly in the nuclei. Previous extraction of secretory fluid from the prostates caused about 60% decrease in the probasin content of isolated nuclei. These suggest that probasin was originally a secretory component in the prostates, being redistributed from the secretory fluid and granule into nuclei during fractionation of subcellular components. 相似文献
916.
Further studies on the acid-precipitable radioactive substance formed during perfusion of Langendorff rat hearts with [14C]adenosine have shown that very brief (30 s) ischaemia causes a sudden rise (20–35%) in its level in the tissue which is followed by the steady fall we have previously described. Analysis of the products of alkaline hydrolysis of this compound shows that at least 96% of the radioactivity appears in the form of a mixture of 2- and 3-AMP as would be expected for RNA while its relatively high resistance to dilute alkali suggests that it is poly A. Subcellular localization studies indicate that radioactivity enters all compartments of the cell, with maximum label in the nucleus. However, a significant proportion is present in the mitochondria and may be poly A acting as the mitochondrial storage form of adenine nucleotides whose existence we have proposed. 相似文献
917.
Spontaneous missense mutations in the rplX gene for ribosomal protein L24 from Escherichia coli. 总被引:2,自引:1,他引:1
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Temperature-resistant pseudorevertants of the temperature-sensitive Escherichia coli mutant KNS19, harboring a mutation in rplX, the gene for ribosomal protein L24, were isolated, cloned, and sequenced. The codon GAC for the amino acid Asp in the temperature-sensitive mutant corresponding to position 84 in the protein chain mutated either back to the wild type (Gly) or to codons for the amino acids Tyr and Glu. Furthermore, rplX genes from two other mutants with an altered protein L24 were cloned and sequenced. The mutations were localized at position 56 (Gly to Asp) and at position 62 (Glu to Lys) in the rplX gene. The latter two mutants lacked a conditional lethal phenotype. The results suggest that the amino acid Gly at positions 56 and 84 in the protein might be involved in loop formations. 相似文献
918.
G Koh Y Seino K Tsuda S Nishi H Ishida J Takeda H Fukumoto T Taminato H Imura 《Life sciences》1987,40(11):1113-1118
2[2-(4.5-Dihydro-1H-imidazol-2-yl)-1-phenylethyl] pyridine dihydrochloride sesquihydrate (DG-5128) is an alpha 2-specific-adrenergic antagonist. We have studied the effect of DG-5128 on insulin and somatostatin release from the isolated perfused rat pancrease. DG-5128 stimulated somatostatin and insulin release not only at a low glucose concentration but also at a high glucose concentration. These findings suggest that an alpha 2-adrenergic receptor plays an important role in the regulation of insulin and somatostatin secretion. 相似文献
919.
Tomoyuki Kawamoto Mieko Nishi Kojiro Takahashi Toshio Nishiyama J. Denry Sato Shigehiko Taniguchi 《In vitro cellular & developmental biology. Plant》1989,25(10):965-970
Summary The stimulatory effects of transforming growth factor β (TGF-β) on epidermal growth factor (EGF)-dependent growth of adult
and newborn human fibroblasts were investigated. EGF-stimulated growth in low serum of dermal fibroblasts from a 41 year-old
adult (HSF-41) was less than half that of newborn foreskin fibroblasts (HFF). The EGF-stimulated growth of HFF after 55 population
doublings (HFF-55) was similarly reduced. The decreased growth response to EGF of fibroblasts, agedin vivo andin vitro appeared to result principally from a decreased sensitivity to EGF due to a decreased number and affinity of high affinity
EGF receptors (H-EGFR). Pre-incubation of HSF-41 and HFF-55 with 25 pM TGF-β enhanced the growth responses of these cells
to EGF and increased the levels of high affinity EGF-binding by these cells Thus, the stimulation by TGF-β of EGF-dependent
growth of human fibroblasts agedin vivo orin vitro is mediated by increased levels of high affinity EGF binding.
This research was supported in part by a grant-in-aid for scientific research (61480388) and a special project research grant
to Okayama University from the Japanese Ministry of Education, Science and Culture.
Editor's statement TGF beta interaction with its receptor is known to affect EGF receptors. In this paper a functional biological
association is established. 相似文献
920.
Keisuke Makino Hiromasa Imaishi Shuuji Morinishi Takuya Hagiwara Tamio Takeuchi Akira Murakami Masatoshi Nishi 《Free radical research》1989,6(1):19-28
In order to overcome a common problem in spin trapping with high concentrations of 5.5-dimethyl-I-pyrroline-N-oxide (DMPO) where ESR spectra are obtained which include an unidentified set of lines composed of a triplet of doublets. commercial DMPO was analyzed for its impurities by high-performance liquid chromatography. mass spectrometry. and nuclear magnetic resonance spectroscopy. It has been determined that this undesirable ESR spectrum IS due to an impurity included in the spin trap. This compound has been assigned to the hydronylunine which is a DMPO-derivative having an epoxy ring located at the 2 and 3 positions. 相似文献