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11.
Satoh Hiroyuki; Okada Mitsumasa; Nakayama Katsumi; Murata Teruyo 《Plant & cell physiology》1985,26(5):931-940
Ribulose 5-phosphate (Ru5P) kinase (ATP:D-ribulose 5-phosphate1-phosphotrans- ferase; EC 2.7.1.19
[EC]
), an enzyme in the reductivepentose phosphate cycle, was purified from the green alga Bryopsismaxima and its activity and peptide composition were studied.The specific activity of purified Ru5P kinase was 20 µmoleRuBP formed (mg protein)1 min1 corresponding toa 490-fold purification from the supernatant of chloroplasts.The Km values of Ru5P kinase for ATP and Ru5P were 69 µMand 330 µM, respectively. The molecular size of Ru5P kinase was estimated as 90 kDa bygel filtration and that of its polypeptide as 41 kDa by SDS-polyacrylamidegel electrophoresis. A small portion of the Ru5P kinase wasfound in a large molecular state (500 kDa) which was consideredto be an inactive form of the enzyme. Ru5P kinase activity has been reported in the pyrenoid of Eremosphaeraviridis as well as ribulose 1,5-bisphosphate carboxylase-oxygenase(RuBisCO) and ribose 5-phosphate isomerase activity (Holdsworth1971). In Bryopsis maxima, among the pyrenoid polypeptides otherthan that of RuBisCO, we found a polypeptide of 42 kDa, similarto that of Ru5P kinase in molecular size and ratio to RuBisCO.A peptide map of the 42 kDa pyrenoid polypeptide, however, showedthat it differed from that of Ru5P kinase. In conclusion, Ru5Pkinase may be not involved in the pyrenoid of this alga. (Received January 19, 1985; Accepted May 15, 1985) 相似文献
12.
Shin-ichi Miyoshi Katsumi Sugiyama Hiroshi Furuta Noriko Miyoshi Sumio Shinoda 《FEMS microbiology letters》1986,34(3):301-304
Abstract Vibrio vulnificus protease (VVP) stimulated histamine release from isolated mast cells in a dose- and temperature-dependent manner within a range of 0.2–4.0 μ g/0.5 ml. Histamine release was accompanied by degranulation, and no leakage of lactate dehydrogenase from cells was observed, indicating that the histamine release was not due to cytolysis but to exocytosis. This release, completed within 30 s at 37°C, suggested that the mechanism of action of VVP on mast cells is different from that of other proteases, such as trypsin or α-chymotrypsin, which release histamine from the cells slowly. 相似文献
13.
Green Lavandula vera callus that produced biotin was preservedsuccessfully in liquid nitrogen for up to 3 weeks. We foundthat the callus recovered after the freeze-preservation, retainingnot only the biosynthetic capability for biotin but also differentiationpotentials such as chloroplast development and plantlet formation.The significance of retention of the metabolic and differentiationpotentials of the callus is discussed in terms of the freeze-preservationof plant genetic resources.
* This study is dedicated to the late Professor J. Ashida. (Received September 1, 1982; Accepted November 5, 1982) 相似文献
14.
15.
Ryousuke Takahashi Katsumi Kawamura Jianguo Hu †Michiyuki Hayashi Takeo Deguchi 《Journal of neurochemistry》1996,67(2):525-529
Abstract: To study the level of ciliary neurotrophic factor (CNTF) in human nervous tissues, we developed a sensitive enzyme-linked immunoassay using a specific antibody against human CNTF. This method allowed us to detect as little as 0.3 ng/ml of human CNTF with good linearity and accuracy. Using this method, CNTF levels were determined in human sciatic nerves obtained at autopsy from 21 amyotrophic lateral sclerosis (ALS) patients and 48 subjects who had died of other neurological diseases. CNTF genotypes were also determined. The results indicated that CNTF levels were high in the normal homozygotes and approximately halved in the heterozygote subjects. There was, however, no significant difference in CNTF levels in the sciatic nerves between ALS and other neurological disease patients, indicating that the CNTF level was mainly determined by its genotypes and that the level in the sciatic nerves was not reduced in ALS patients. 相似文献
16.
Neutral red (NR) in the culture medium entered the vacuolesof a green alga, Micrasterias pinnatifida, at a higher rateat pH 8 than at pH 5. NR remained soluble in vacuoles of cellscultured at pH 5, while it precipitated and formed granulesin cells cultured at pH 8. The vacuoles of cells cultured atpH 8 contained fibrils, but those of cells cultured at pH 5did not. The amount of NR that entered the cells was markedlyreduced by the addition to the medium of nigericin at 10-5M,monensin at 10-5M, bafilo-mycin A1 at 10-5M, or ammonium chlorideat 50 mM. The formation of NR granules in vacuoles were stronglyinhibited and the disorganization of NR granules were acceleratedby the addition of nigericin at 10-5M, or bafilomycin A1 at10-5M to the culture medium. The possibility is discussed thatNR which enters vacuoles might become positively charged (NRH+)by protons brought into vacuoles by proton pumps and that NRH+might combine with some negatively charged macromolecules toform aggregates or granules. (Received April 18, 1996; Accepted May 27, 1996) 相似文献
17.
Sub Sunoo Katsumi Asano Fumiyuki Mitsumori 《European journal of applied physiology and occupational physiology》1996,74(4):305-310
We measured ATP, phosphocreatine (PCr), inorganic phosphate (Pi), and the intracellular pH in rat hindlimb muscles during submaximal isometric exercise with various O2 deliveries using31P nuclear magnetic resonance spectroscopy (31P NMR) to evaluate changes in energy metabolism in relation to O2 availability. Delivery of O2 to muscles was altered by controlling the fractional concentration of inspired oxygen (F
IO2) at 0.50, 0.28, 0.21, 0.11 and 0.08 with monitoring partial pressure of oxygen and carbon dioxide, and bicarbonate at the femoral artery. The steady-state ratio of PCr : (PCr + Pi) during exercise decreased as a function ofF
IO2 even at 0.21. Significant acidification of the intracellular pH during exercise occurred at 0.08F
IO2. Change in the PCr : (PCr + Pi) ratio demonstrated that the oxidative capacity, i.e. the maximal rate of the oxidative phosphorylation reaction, in muscle was not limited by O2 delivery at 0.50F
IO2, but was significantly limited at 0.21F
IO2 or below. Change in the intracellular pH at 0.08F
IO2 could be interpreted as an increase in lactate, suggesting activation of glycolysis. Correlation between the PCr : (PCr + Pi) ratio and the intracellular pH revealed the existence of a critical PCr : (PCr + Pi) ratio and pH for glycolysis activation at around 0.4 and 6.7, respectively. 相似文献
18.
Katsumi Mominoki Noriko Nakagawa-Tosa Masami Morimatsu Bunei Syuto Masayuki Saito 《Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology》1995,110(4):785-789
Haptoglobin (Hp), a hemoglobin-binding protein in plasma, consists of α and β subunits and has a tetra-chain arrangement (β-α-α-β) connected by disulfide bridges in most mammals so far examined. Dog Hp has been reported to be unique compared with other Hps in respect that (1) the two αβ units are joined by a non-covalent interaction rather than a disulfide bridge and (2) the α chain has an oligosaccharide-binding sequence (Asn-X-Ser/Thr) and is glycosylated. To determine whether the unique structures of dog Hp are common in the Carnivora, we purified Hps from sera of bear and cat, and analyzed their subunit structure and partial amino acid sequences. The analyses by gel filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, under both reducing and non-reducing conditions, revealed that bear and cat Hps have similar subunit arrangements to dog Hp, suggesting the absence of a disulfide bridge between two α chains. This was confirmed by amino acid sequence analysis of the α chains: that is, Cys15 participating in the inter-α chain disulfide bridge was replaced by Val in bear or Leu in cat and dog. Thus, the unique subunit arrangement of Hp reported in dog may be common in the Carnivora. In contrast to dog Hp, however, α chains of bear and cat Hps were found not to have the typical oligosaccharide binding sequence on their α chains and were not glycosylated. 相似文献
19.
Mayumi Nishikata Aki Nakai Hitomi Fushida Keishiro Miyake Takaichi Arita Ken Iseki Katsumi Miyazaki Akikazu Nomura 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1993,612(2)
A method is described for the simultaneous determination of (+)- and (−)-homochlorcyclizine (HCZ) in human urine by high-performance liquid chromatography on a chiral stationary phase of ovomucoid-bonded silica. The pH of the buffer and organic modifier in the mobile phase markedly affected the chromatographic separation. A mobile phase of methanol—0.02 M acetate buffer (pH 4.7) (25:75, v/v) at a flow-rate of 1.0 ml/min was used for the urine assays. The ultraviolet absorption was monitored at 240 nm, and diphenhydramine was employed as the internal standard for the quantitation. (+)-HCZ, (−)-HCZ and the internal standard were eluted at retention times of 15, 25 and 8 min, respectively. The limit of determination for HCZ enantiomers was ca. 50 ng/ml of urine. One of the metabolites in human urine, which was a quaternary ammonium-linked glucuronide, could also be determined in a manner similar to unchanged HCZ after β-glucuronidase hydrolysis. A pharmacokinetic study was conducted with three healthy volunteers, who each received a single oral dose of racemic HCZ (20 mg). Distinct differences were found between the two enantiomers, particularly in the metabolic process, that is, the urinary excretion as (−)-HCZ-glucuronide within 48 h was ca. four times higher than that of the (+)-isomer. This method should be very useful for enantioselective pharmacokinetic studies of HCZ. 相似文献
20.
Douglas E Bassett Jr Munira A Basrai Carla Connelly Katherine M Hyland Katsumi Kitagawa Melanie L Mayer Dwight M Morrow Andrew M Page Vicente A Resto Robert V Skibbens Philip Hieter 《Current opinion in genetics & development》1996,6(6):763-766
The completion of the genome sequence of the budding yeast Saccharomyces cerevisiae marks the dawn of an exciting new era in eukaryotic biology that will bring with it a new understanding of yeast, other model organisms, and human beings. This body of sequence data benefits yeast researchers by obviating the need for piecemeal sequencing of genes, and allows researchers working with other organisms to tap into experimental advantages inherent in the yeast system and learn from functionally characterized yeast gene products which are their proteins of interest. In addition, the yeast post-genome sequence era is serving as a testing ground for powerful new technologies, and proven experimental approaches are being applied for the first time in a comprehensive fashion on a complete eukaryotic gene repertoire. 相似文献