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1.
Hirotaka Yamamoto Hidehiko Konno Teiji Yamamoto Kitae Ito Michinao Mizugaki Yuzo Iwasaki 《Journal of neurochemistry》1987,49(2):603-609
Glutamine synthetase (GS) isolated from human brain formed a single band on sodium dodecyl sulfate-polyacrylamide gel with a molecular weight of 44,000. The enzyme had a specific activity of 179.2 U/mg protein when assayed by measuring the rate of the formation of gamma-glutamylhydroxamate using hydroxylamine as a substrate. In the presence of manganese ions, the relative activity of human brain GS was much lower than that of the sheep brain enzyme. The suppression of activity by increasing the ADP concentration, however, was less marked in the human enzyme than that in the sheep enzyme. Antibodies were raised in rabbits against the purified enzyme. The double-immunodiffusion technique disclosed cross-reactivities among GSs isolated from human, sheep, and rat brains, but the enzymes were not immunologically identical. Immunohistochemically, GS was localized in the cytoplasm of astrocytes in the human and rat brains and in pericentral hepatocytes of the liver. 相似文献
2.
Junichi Ishihara Nagahiro Saijo Yasutsuna Sasaki Hidehiko Nakano Akira Ozaki Hidenobu Takahashi Masanori Sakurai Kazuhiko Nakagawa Masaaki Iigo Fumihiko Kanzawa Akio Hoshi Weon Seon Hong James R. Jett Terumi Takahashi 《Cancer immunology, immunotherapy : CII》1987,24(3):185-189
Summary The antitumor effect of recombinant human tumor necrosis factor (rH-TNF) on two clones of rat fibrosarcoma with different metastatic potential to lymph nodes was examined. The colony formation of clone A, which has high metastatic potential, was completely inhibited by continuous exposure to rH-TNF at 50 U/ml. In contrast, colony formation of clone G, which has low metastatic potential, was not inhibited by high concentrations of rH-TNF (10,000 U/ml). The inhibitory effect of rH-TNF on colony formation by clone A was also observed with a 1-h exposure to rH-TNF. This effect was time and concentration dependent, as determined by the colony assay, 3H-thymidine uptake assay, and 51Cr-release assay. 3H-thymidine and 3H-uridine uptake per cell of clone A exposed to rH-TNF was not decreased. This suggests that the mechanisms of the antitumor effect of rH-TNF were not due to inhibition of DNA and RNA synthesis of tumor cells. In vivo growth and lymph node metastases of clone A inoculated i.p. to Donryu strain rats were completely suppressed by 14 consecutive i.p. injections of 105 or 106 U/kg per day of rH-TNF. On the other hand the growth of clone G was not influenced by rH-TNF administration. 相似文献
3.
Y Ochiai T Kobayashi S Watabe K Hashimoto 《Comparative biochemistry and physiology. B, Comparative biochemistry》1990,95(2):341-345
1. Myosins were prepared from the ordinary muscle of 16 fish species as well as from rabbit fast muscle, and light chain subunits [alkali light chains A1, A2 and DTNB (5,5'-dithio-bis-2-nitrobenzoate) light chain] were separated on two-dimensional gel electrophoresis in combination with isoelectric focusing and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. 2. A1 light chains showed mol. wts ranging from 21,000 to 22,900 and isoelectric points ranging from 4.51 to 4.62. DTNB light chains were spotted in a narrow area, with a mol. wt range of 16,800-17,600 and an isoelectric point range of 4.48-4.55. On the other hand, A2 light chains were most species-specific, with a mol. wt range of 14,000-19,500 and an isoelectric point range of 4.31-4.46. 3. It was suggested that the lower species-specificity in A1 as opposed to A2 is accounted for by the addition of an N-terminal peptide ("difference peptide") in the former. The properties and possible role of this peptide are discussed. 相似文献
4.
Sueyoshi Kuni; Kubo Yoshihiro; Yamagishi Kenji; Ogura Nagao; Ochiai Kuniyasu; Fukushima Kazuo; Ikeda Tadashi; Nakagawa Hiroki 《Plant & cell physiology》1988,29(6):975-980
Two monoclonal antibodies, 17(3)9 and 36(79)4, were preparedagainst nitrate reductase from Spinacia oleracea L. leaves.An enzyme-linked immunosorbent assay showed that 17(3)9, butnot 36(79)4, reacted more strongly to heat-denatured than nativeantigen. These antibodies inhibited NADH-nitrate reductase aswell as its various partial activities including reduced methylvilogen-nitrate reductase, reduced flavin mononucleotide-nitratereductase and NADH-cytochrome c reductase activities, but notNADH-ferricyanide reductase activity. Immunoblotting after electrophoreticseparation of nitrate reductase fragments obtained by Staphyrococcusaureus V8 protease digestion of native enzyme revealed thatthe two monoclonal antibodies bind to different epitopes locatedon the 28 kDa of the NADH-ferricyanide reductase domain. (Received October 2, 1987; Accepted June 9, 1988) 相似文献
5.
Gyu-Chul Hwang Yoshihiro Ochiai Shugo Watabe Kanehisa Hashimoto 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1991,161(2):141-146
Summary Heavy meromyosin subfragment-1 (S1) was prepared by -chymotrypsin from myosin of carp acclimated to either 10°C or 30°C for a minimum of 5 weeks. The objective of these studies was to document thermally-induced changes in the myosin molecule and to extend previous observations. Ca2+- and K+ (EDTA)-ATPase activities of cold-acclimated carp S1 were 1.1 and 0.8 mol Pi·min-1·mg-1, respectively, and these values did not differ significantly from those of warm-acclimated carp. The inactivation rate constant (KD) of S1 from cold-acclimated carp was 32.1x10-4· s-1, compared to 13.2x10-4·s-1 for warm-acclimated carp. The maximum initial velocity of acto-S1 Mg2+-ATPase activity at pH 7.0 in 0.05 M KCl was 9.3 s-1 with cold-acclimated carp, about 3.7 times higher than that for warm-acclimated carp. However, no significant difference was observed in the apparent affinity of S1 to actin. Peptides maps of the heavy chain of S1 were different and suggested distinct isoforms for the myosins from warm- and cold-acclimated muscle.Abbreviations
ATPase
adenosine 5-triphosphatase
-
DTNB
5,5-dithiobis (2-nitrobenzoic acid)
-
DTT
dithiothreitol
-
EDTA
ethylenediaminetetraacetic acid
-
EGTA
ethyleneglycol bis (-aminoethylether)-N,N,N,N-tetraacetic acid
-
K
D
inactivation rate constant
-
K
m
apparent dissociation constant
-
P
i
inorganic -phosphate
-
PMSF
phenylmethane-sulfonyl fluoride
-
S
1
heavy meromyosin subfragment-1
-
SDS
sodium dodecyl sulfate
-
SDS-PAGE
SDS-polyacrylamide gel electrophoresis
-
TPCK
N-tosyl-l-phenylalanyl chloromethyl ketone
-
V
max
maximum initial velocity 相似文献
6.
Hitoshi Shibata Hideo Ochiai Tetsufumi Kawashima Tadayoshi Okamoto Isamu Inamura 《BBA》1986,852(2-3):175-182
By mixing chlorophyll (Chl) a or b with a dense bovine serum albumin solution, the water-soluble Chl-bovine serum albumin complexes were prepared. These complexes, eluted near the void volume on a gel filtration, were separated well from unreacted bovine serum albumin, indicating an aggregation of such molecules in the complexes. Preparation of chlorophyllide (Chlide) a- or Chlide b-bovine serum albumin complex was unsuccessful, while the phytol-, and β-carotene-bovine serum albumin complexes could be obtained. Chls in the Chl-bovine serum albumin complexes had the following characteristics. (i) Main absorption peak of Chl a or b in the red region occurred at 675 nm or 652 nm, respectively. The Chl a-bovine serum albumin complex having absorption peak at 740 nm was also prepared. As compared with the stabilities of Chl a and b in Triton X-100. (ii) Both Chls in the bovine serum albumin-complexes were stable against oxidative stresses, such as photobleaching, Fenton reagent, peroxidase-H2O2 system. But (iii) they were easily hydrolyzed by chlorophyllase. These properties of Chls in the bovine serum albumin-complexes were similar to those of Chls in the isolated light-harvesting Chl a/b protein complex. A possible localization of Chls within the bovine serum albumin complexes was suggested that the porphyrin moiety of Chl was buried in bovine serum albumin; however, the hydrophilic edge of porphyrin ring, adjacent to the phytol group, occurred in the hydrophilic region of a bovine serum albumin molecule. 相似文献
7.
Tatsuhide Kunishita Takeshi Tabira Hidehiko Umezawa Makoto Mizutani Yasutomi Katsuie 《Journal of neurochemistry》1986,46(1):105-111
Biochemical and morphological studies were done on a new trembling mutant hamster CBB. The yield of myelin from the mutant was 30 and 40% of the control at 46 and 140 days of age, respectively, but myelin composition and 2',3'-cyclic nucleotide-3'-phosphohydrolase (CNPase) activity were normal. Morphologically, about 18% of the axons were myelinated in the mutant optic nerve at 46 days of age, in which the myelinated fibers were those with larger diameters (more than 0.6 micron), while the control had a peak at 0.4 micron in diameter. The ultrastructure and thickness of compact myelin lamellae in the mutant were normal. Myelination and the structure of peripheral nerve myelin appeared normal. The results indicate that the essential defect is the delay and arrest of myelination in the CNS, which is probably caused by either a decreased rate of synthesis of myelin components in oligodendrocytes or a defect in the oligodendrocyte-axon recognition in smaller axons. 相似文献
8.
Activated c-raf gene in a rat hepatocellular carcinoma induced by 2-amino-3-methylimidazo[4,5-f]quinoline 总被引:8,自引:0,他引:8
F Ishikawa F Takaku M Ochiai K Hayashi S Hirohashi M Terada S Takayama M Nagao T Sugimura 《Biochemical and biophysical research communications》1985,132(1):186-192
A rat hepatocellular carcinoma, IQ7, induced by 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) gave two transformants of NIH 3T3 cells on DNA mediated gene transfer. One of these transformants was examined further and secondary and tertiary transformants were obtained. The secondary transformant was tumorigenic in nude mice. The activated oncogene in this primary transformant was identified as rat c-raf by Southern blot analysis. 相似文献
9.
The properties and application of l-methionine γ-lyase [methioninase, l-methionine methanethiol-lyase (deaminating), EC 4.4.1.11], a pyridoxal 5′-phosphate enzyme, purified from Pseudomonas putida and Aeromonas sp. are presented. The enzyme has multicatalytic functions: it catalyses α,γ-elimination and γ-replacement reactions of l-methionine and its analogues (e.g. ethionine, homocysteine, O-acetylhomoserine and selenomethionine), α,β-elimination and β-replacement reactions of l-cysteine and its analogues (e.g. S-methylcysteine, O-acetylserine and Se-methylselenocysteine), deamination and γ-addition of vinylglycine, and deuterium labelling at the α and β positions of l-methionine and other straight-chain l-amino acids. These reactions are applicable to the synthesis of various optically active sulphur and selenium amino acids, preparation of deuterium or tritium labelled l-amino acids, and determination of sulphur amino acids. In addition, the enzyme shows potent anti-neoplastic activity. 相似文献
10.
Relationship between beta-lactamase activity and resistance to beta-lactam antibiotics in Mycobacterium smegmatis 总被引:1,自引:0,他引:1
Penicillin-susceptible mutants and beta-lactamase-negative mutants were isolated from Mycobacterium smegmatis after nitrosoguanidine mutagenesis. Both the mutants were found to be susceptible to low levels of penicillin and cephalosporins by twofold dilution testing. Clavulanic acid reduced the minimal inhibitory concentrations of beta-lactamase-labile beta-lactams for the penicillin-susceptible mutants and the parent strain, but had no effect on the susceptibility of the beta-lactamase-negative mutants. Comparison of the beta-lactamase activities found in these mutants and the parent strain indicated that there was a rough correlation between the beta-lactamase level in these organisms and their susceptibility to beta-lactams. 相似文献