巻号一覧
76 巻, 2 号
選択された号の論文の23件中1～23を表示しています
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II. Composition of Pigments and Electron Transfer SystemsYuzo SHIOI, Ken-ichiro TAKAMIYA, Mitsuo NISHIMURA1974 年 76 巻 2 号 p. 241-250
発行日: 1974/08/25
公開日: 2008/11/18
ジャーナル フリーThe composition of photosynthetic pigments and electron transfer components in the cells of Chloropseudomonas ethylica strain 2-K was investigated.
The cells of C. ethylica contained, per mg protein, 97.8 nmoles of chlorobium chlorophyll-660 (bacteriochlorophyll c), 5.7 nmoles of bacteriochlorophyll a, 0.064 nmole of reaction center chlorophyll (P840), 1.69 nmoles of total heme proteins (heme basis), 26.3 nmoles of total non-heme iron, 0.59 nmole of total acid-extractable flavins, and 4.9 nmoles of menaquinone. There are approximately 1, 530 molecules of chlorobium chlorophyll-660 and 89 molecules of bacteriochlorophyll a per molecule of the reaction center pigment (P840). The high chlorophyll content may be an adaptation to the low light intensity habitat of this organism.
The cells contained approximately 0.63 nmole of cytochrome c-551.5 and approximately 1.06 nmoles of cytochrome c-555 (550) (both on a heme basis) per mg protein. Cytochrome c-551.5 was less firmly bound to cellular structures than cytochrome c-555 (550). There was no indication of the presence of cytochrome c-553 or B-type cytochrome in the reduced-minus-oxidized difference spectra or in the pyridine hemochrome spectra of whole cell, particle or soluble fractions. The mode of reduction of cytochrome c-555 (550) by sodium ascorbate was significantly different in the free and bound states.抄録全体を表示PDF形式でダウンロード (751K) -
X. Sources of Energy and Energy Coupling Reactions of the Active Transport Systems for Isoleucine and Proline in E. coliHiroshi KOBAYASHI, Emi KIN, Yasuhiro ANRAKU1974 年 76 巻 2 号 p. 251-261
発行日: 1974/08/25
公開日: 2008/11/18
ジャーナル フリーThe sources of energy and energy coupling reactions of the active transport systems for isoleucine and proline in Escherichia coli cells were studied.
It was concluded that the isoleucine transport system utilizes ATP molecule as an energy source and that the initial rate of isoleucine uptake is directly correlated with the cellular concentration of ATP.
Active uptake of proline, on the other hand, is generated by an “energized” membrane state of the cells and does not depend on the cellular concentration of ATP. Results suggested that a coupling factor of oxidative phosphorylation generates the “energized” membrane state utilizing cellular ATP in the absence of respiration.
All studies were carried out using Escherichia coli strain NR-70 which lacks membrane-bound, Mg2+-requiring adenosine triphosphatase [EC 3. 6. 1. 3]. The NaN3-sensitive, Mg2+-requiring adenosine triphosphatase and the respiratory and oxidative phosphorylating activities of the mutant were extensively analyzed. It was concluded that the NaN3-sensitive, Mg2+-requiring adenosine triphosphatase functions as a coupling factor of oxidative phosphorylation and that the mutant is defective in this enzyme activity.抄録全体を表示PDF形式でダウンロード (955K) -
IV. A Novel Protein Repressing RNA Polymerase IIShunji NATORI, Kazuyuki TAKEUCHI, Den'ichi MIZUNO1974 年 76 巻 2 号 p. 263-270
発行日: 1974/08/25
公開日: 2008/11/18
ジャーナル フリーA protein was isolated which repressed RNA polymerase II [EC 2. 7. 7. 6] of Ehrlich ascites tumor cells. This protein, named R protein, was only inhibitory when native DNA was used as template with homologous RNA polymerase.
This protein had affinity for DNA. It was inhibitory when added at the initiation stage of transcription, but not when added once transcription had started. Its molecular weight was estimated as 38, 000 daltons by polyacrylamide gel electrophoresis containing sodium dodecylsulfate.
The R protein did not affect the size of RNA synthesized in vitro. Studies on its effect on RNA synthesis in the presence of S-II, a factor stimulating RNA polymerase II of Ehrlich ascites tumor cells, suggested that R protein preferentially repressed synthesis of a certain species of RNA which is synthesized in the presence of S-II.
The molecular mechanism of the inhibition of RNA synthesis by this protein is discussed.抄録全体を表示PDF形式でダウンロード (1474K) -
V. Quantitative Analyses of the Formation of the Kinetically Inactive Complex of Cytochrome Oxidase with CyanideShinya YOSHIKAWA, Yutaka ORII1974 年 76 巻 2 号 p. 271-281
発行日: 1974/08/25
公開日: 2008/11/18
ジャーナル フリーDuring inhibition studies of cyanide on cytochrome oxidase [EC 1. 9. 3. 1], we have shown that a kinetically inactive complex is formed between cyanide and an intermediate species of cytochrome oxidase which occurs only in the functioning state, and that this intermediate can be recognized from the steady-state absorption spectrum (1). In the present investigation, the interaction of cyanide with the intermediate was examined spectrophotometrically and manometrically under controlled conditions, and the experimental data were analyzed statistically to improve the accuracy of the thermodynamic parameters presented previously (1).
When various concentrations of cyanide were added to the cytochrome oxidase system, which consisted of ascorbate amounting to not less than 0.2M, 0.6μM cytochrome c, 15μM cytochrome oxidase, and molecular oxygen, in the aerobic steady state, a series of absorption spectra appeared with clear isobestic points as the cyanide concentration was increased, indicating a reaction system of two spectrally distinct components. This spectral change was interpreted in terms of a simple bimolecular reaction E+I=EI with a dissociation constant of 0.2μM, and the concentration of cyanide-binding sites was estimated as half of the total heme a concentration. The same treatment was applied to the experimental results of manometric assays, giving similar parameters.
The spectrally distinct components are not necessarily single chemical species. These spectral changes can be explained by a reaction system comprising many species, but only if the relative concentrations of all the enzyme species either free from or bound with the inhibitor are independent of the inhibitor concentration. The experimental conditions leading to such relations are presented with theoretical considerations.抄録全体を表示PDF形式でダウンロード (871K) -
IV. Crystalline Tu•GTP, Tu•Gpp (CH2) p, and Phenylalanyl-tRNA•Tu•GTP ComplexKen-ichi ARAI, Masao KAWAKITA, Yoshito KAZIRO1974 年 76 巻 2 号 p. 283-292
発行日: 1974/08/25
公開日: 2008/11/18
ジャーナル フリーPolypeptide elongation factor Tu has been purified from E. coli as Tu•GDP and Tu•Ts complexes, and both of them were crystallized (K. Arai, M. Kawakita, and Y. Kaziro, J. Biol. Chem., 247, 7029 (1972)). In this communication we describe a procedure for the preparation of crystalline Tu-GTP, Tu•Gpp (CH2) p, and (phenylalanyl-tRNA)•Tu•GTP complexes. The preparation of (phenylalanyl-tRNA)•Tu•Gpp (CH2) p is also described.抄録全体を表示PDF形式でダウンロード (1764K) -
V. Properties of Various Complexes Containing EF-Tu and EF-TsKen-ichi ARAI, Masao KAWAKITA, Yoshito KAZIRO1974 年 76 巻 2 号 p. 293-306
発行日: 1974/08/25
公開日: 2008/11/18
ジャーナル フリー1. Free EF-Tu is extremely unstable, being inactivated almost completely at 40°C within 5min, but it is markedly stabilized by GDP, EF-Ts, GTP, 5'-guanylylmethyl-enediphosphonate (Gpp (CH2) p), and Phe-tRNA plus GTP. EF-Ts is heat stable, full activity being retained after heating for 5min at 60°C. The pH stability of EF-Tu, EF-Ts, the complex of EF-Tu and GDP (Tu•GDP), and the complex of EF-Tu and EF-Ts (Tu•Ts) is also described.
2. The optimal pH for the Tu•GDP_??_[3H] GDP exchange reaction catalyzed by EF-Ts is around pH 8.0.
3. Dissociation constants of Tu•GDP in the presence and absence of Mg2+ ions are 4.9×10-9M, and 2.2×10-6M, respectively. Those of Tu•Ts, Tu•GTP, and Tu•Gpp (CH2) p are 7.7×10-9M, 3.6×10-7M, and 2.2×10-6M, respectively. Ternary complexes, (Phe-tRNA)•Tu•GTP and (Phe-tRNA)•Tu•Gpp (CH2) p, dissociate into Phe-tRNA and Tu•nucleotide complexes with dissociation constants of 7.2×10-8M and 2.5×10-7M, respectively.
4. The first order rate constant for dissociation (k-1) of Tu•GDP is 3.4•10-4 sec-1 at 0°C. The second order rate constant for association (k+1) of EF-Tu and GDP is 3.1×105M-1•sec-1 at 0°C. Similarly defined rate constants k-1 and k+1 of Tu•GTP are 5.0×10-2 sec-1 and 1.1×105M-1•sec-1, respectively. Both the k+1 and k-1 values are markedly affected by temperature.
5. The ratio of k-1 to k+1 agrees well with the dissociation constants of Tu•GDP and Tu•GTP. The dissociation constants are little affected by temperature.抄録全体を表示PDF形式でダウンロード (991K) -
The Differential Specificities of the Enzymes from Streptomyces griseus and Diplococcus pneumoniaeMidori ARAKAWA, Takashi MURAMATSU1974 年 76 巻 2 号 p. 307-317
発行日: 1974/08/25
公開日: 2008/11/18
ジャーナル フリーEndo-β-N-acetylglucosaminidase H from Streptomyces griseus completely hydrolyzed thyroglobulin Unit A (mannose-N-acetylglucosamine unit) glycopeptides, but did not act on “side-chain*-free” thyroglobulin Unit B (complex heteropolysaccharide unit) glycopeptides. Endo-β-N-acetylglucosaminidase H also did not act on intact or “side-chain-free ” IgG glycopeptides. α-L-Fucosidase [EC 3. 2. 1. 51] treatment did not make the above glycopeptides susceptible to endo-β-N-acetylglucosaminidase H.
[14C]-Acetyl-AsnGlcNAc2Man1 prepared from [14C]-acetyl-AsnGlcNAc2Man5 by α-mannosidase [EC 3. 2. 1. 24] digestion was resistant not only to endo-β-N-acetyl-glucosaminidase H, but also to endo-β-N-acetylglucosaminidase D from Diplococcus pneumoniae.
A disaccharide isolated from a “side-chain-free” bovine IgG glycopeptide by treatment with endo-β-N-acetylglucosaminidase D, followed by α-mannosidase digestion had a probable structure of Manβ1→4GlcNAc, suggesting that a common sequence of the mannose-N-acetylglucosamine unit (Manβ1→4GlcNAcβ1→4GlcNAc→Asn) is present in glycopeptides of complex heteropolysaccharide unit.
We propose that endo-β-N-acetylglucosaminidase H and endo-β-N-acetylglucosaminidase D have opposite specificities; i.e., the former generally hydrolyzes glycopeptides of the mannose-N-acetylglucosamine unit, and the latter generally hydrolyzes “side-chain-free” glycopeptides of the complex heteropolysaccharide unit, and that the two enzymes recognize the structural differences of α-mannosyl residues in the oligomannosyl cores of the two units.抄録全体を表示PDF形式でダウンロード (892K) -
Ikuo FUNAKOSHI, Hiroshi NAKADA, Ikuo YAMASHINA1974 年 76 巻 2 号 p. 319-333
発行日: 1974/08/25
公開日: 2008/11/18
ジャーナル フリーPlasma membranes were isolated from an ascites hepatoma, AH 66, after the cells had been hardened by treatment with fluorescein mercuric acetate (FMA) or Zn ions. The carbohydrate compositions of these plasma membrane preparations, FMA- and Zn-membranes, expressed in terms of molar ratios to one of the major components (glucosamine), were essentially the same and were indicative of the presence of glycoproteins and mucoproteins.
Glycopeptides were prepared on a large scale from FMA-membranes by pronase digestion, then were fractionated into three major fractions, I, II, and III. The distribution of the total carbohydrates found in the pronase digest was roughly 60, 30, and 10% in I, II, and III, respectively. I was a mixture of glycopeptides of relatively low molecular weight, retarded by a Sephadex G-50 column. The carbohydrate moieties were composed mainly of fucose, galactose, mannose, glucosamine, and sialic acid, and appeared to be linked to asparagine through an N-glycosidic (aspartylglycosylamine) linkage. II was a mixture of high molecular weight glycopeptides, excluded from a Sephadex G-50 column. Its carbohydrate moieties were composed mainly of galactose, glucosamine, galactosamine, and sialic acid, and were probably linked to threonine and serine through an O-glycosidic linkage. II was capable of binding to a lectin from Ricinus communis which is galactose or N-acetylgalactosamine specific. III was a mucopolysaccharide identified as heparan sulfate on the basis of its chemical composition, the presence of N-sulfate, electrophoresis on cellulose acetate and its resistance to chondroitinases [EC 4. 2. 2. 4].
Glycopeptides similarly prepared from Zn-membranes gave two fractions corresponding to I and II plus III. From the latter, II and III were identified by electrophoresis on cellulose acetate as identical with II and III from FMA-membranes, respectively.抄録全体を表示PDF形式でダウンロード (4950K) -
In Ciliary Axonemes Isolated from Tetrahymena pyriformisMinoru OTOKAWA1974 年 76 巻 2 号 p. 335-340
発行日: 1974/08/25
公開日: 2008/11/18
ジャーナル フリーCiliary axonemes, isolated from Tetrahymena pyriformis, converted [14C]ADP into ATP and AMP. Based on changes in the distribution of radioactive nucleotides, the activity of the axonemal adenylate kinase [EC 2. 7. 4. 3] was determined. Fairly high adenylate kinase activity was observed in comparison with the axonemal ATPase [EC 3. 6. 1. 3] activity. Rapid turnover of high energy phosphate was observed among ATP, ADP, and AMP. These results support the view that the axonemal adenylate kinase contributes significantly to the maintenance of an effective ATP concentration along the cilium when ATP is supplied from the cell body to the cilium. The enzymic properties of adenylate kinase in cilia seem to be similar to those of the enzyme from other materials.抄録全体を表示PDF形式でダウンロード (380K) -
Keiichi ASO, Michiko YAMASHITA, Soichi ARAI, Masao FUJIMAKI1974 年 76 巻 2 号 p. 341-347
発行日: 1974/08/25
公開日: 2008/11/18
ジャーナル フリーPeptic hydrolysate of a soybean globulin fraction was used as a substrate for the plastein reaction. When a 50% (w/v) solution of the substrate was incubated with pepsin [EC 3. 4. 23. 1] at pH 4.0, the incubation mixture turned turbid as a plastein was formed and its molecular chains assembled. The turbid solution was more-or-less clarified by treatment with any of urea, guanidine hydrochloride, sodium dodecylsulfate, and some alcohols. The turbid solution showed a high affinity for a hydrocarbon (n-heptane). Fluorescence spectroscopy demonstrated that a spectral peak (near 350nm) of the turbid solution was blue-shifted by 7nm from that of clear substrate solution, and also that 1-anilinonaphthalene-8-sulfonate (ANS) treatment of the turbid solution gave rise to a new peak (near 450nm) with an enhanced quantum yield. The turbidity increased with increasing temperature and the plastein-ANS fluorescence showed a blue-shift at the same time. Compared with the substrate, the waterinsoluble product causing the turbidity was found to contain smaller amounts of hydrophilic and larger amounts of hydrophobic amino acid residues. Based on these results it was concluded that hydrophobic forces are a major factor in plastein chain assembly.抄録全体を表示PDF形式でダウンロード (1087K) -
Shoichi NAKASHIMA, Kazuhisa SUGIMURA, Teruo SAWADA, Masanori MAZAKI1974 年 76 巻 2 号 p. 349-357
発行日: 1974/08/25
公開日: 2008/11/18
ジャーナル フリーA heavy conjugate (D31-BαA) of bacterial α-amylase [EC 3. 2. 1. 1] (BαA) with diazotized 4-aminoquinoline 1-oxide (4AQO) was prepared. After removal of the cross-reacting materials in the product with an immunoadsorbent of mouse anti-BαA antibody, D38-BαA was obtained. The reactivity of D38-BαA with anti-BαA antibody was tested by inhibition of passive hemagglutination (PHA) with BαA-coated erythrocytes and the enzymatic procedure. Inhibition of PHA was detected by BαA at 3×10-9M and by D38-BαA at 2×10-5M. The decrease in the neutralizing activity of anti-BαA antibody against BαA by a 4.08×10-5M solution of D38-BαA corresponded. to that obtained with a 5.1×10-8M solution of N-bromosuccinimide-treated BαA (NBS-BαA), which completely lost its enzymatic activity without alteration in its. antigenic properties. It was confirmed that there was little cross-reactivity between native BαA and D38-BαA.
Antisera against D38-BαA contained anti-hapten antibody, but no detectable anti-BαA antibody. However, priming with the same antigen induced the immunological memory of BαA, since enhanced anti-BαA antibody response was observed in these mice primed with D38-BαA. The specificity of enhancement by priming with the modified antigen was demonstrated by the lack of effect on the immune response to Taka-amylase A (TAA). The degree of enhancement induced by various doses of D38-BαA was similar to that observed with 1μg of native BαA. These results. appear to be in good agreement with the general observation that recognition of antigens at the T cell level is less specific than that at the level of B cells.抄録全体を表示PDF形式でダウンロード (692K) -
Nobuo MATSUOKA, Yasushi SAITO, Hiromichi OKUDA, Setsuro FUJII1974 年 76 巻 2 号 p. 359-364
発行日: 1974/08/25
公開日: 2008/11/18
ジャーナル フリーLipid micelles were prepared from isolated fat cells by treatment under hypotonic conditions as reported previously. The micelles were found to have triglyceride synthesizing activity as well as lipolytic activity. Adrenaline and dibutyryl cyclic AMP (DBcAMP) had no effect on triglyceride synthesis, but greatly stimulated lipolysis in the micelles. Calcium ions inhibited triglyceride synthesis and activated lipolysis. Triglyceride synthesizing activity was found in the pellet fraction obtained by centrifuging the micelles at 105, 000×g for 60min. This fraction also contained lipase [EC 3. 1. 1. 3] and esterase [EC 3. 1. 1. 1] activities. Calcium ions inhibited the triglyceride synthesizing activity and activated the lipase activity of the pellet fraction. Based on these results, it was suggested that calcium ions may be important in the lipid metabolism of the micelles.抄録全体を表示PDF形式でダウンロード (487K) -
III. Separation of Two ComponentsKoichi YAGI, Fumio OTANI1974 年 76 巻 2 号 p. 365-373
発行日: 1974/08/25
公開日: 2008/11/18
ジャーナル フリーSubfragment-1 was isolated from rabbit skeletal muscle myosin by chymotryptic digestion. It was shown by gel electrophoresis in the presence of SDS that this subfragment-1 contained g1-chain and g3-chain, but was lacking in g2-chain. The Subfragment-1 migrated as two protein bands on acrylamide-gel electrophoresis under non-dissociating conditions. These two protein components were separated by DEAE-cellulose (DE-32) column chromatography by means of one-step elution using 0.08M KCl-20mM TES buffer (pH 7.5). One component contained g1-chain and the other, g3-chain. The Ca-ATPase activity of the former was about one-third of that of the latter.抄録全体を表示PDF形式でダウンロード (2356K) -
II. Stability and Some Chemical and Kinetic PropertiesYukiho KUBOTA, Shozo SHOJI, Takayuki FUNAKOSHI, Hiroshi UEKI1974 年 76 巻 2 号 p. 375-384
発行日: 1974/08/25
公開日: 2008/11/18
ジャーナル フリーCarboxypeptidase CN [EC 3. 4. 12. 1] is composed of 703 amino acid residues, 32 hexose residues (as galactose), and 5 hexosamine residues (as glucosamine): these are Trp6, Lys29, His18, Arg44, Asp83, Thr37, Ser52, Glu46, Pro14, Gly43, Ala50, Cys(half)6, Val44, Met7, Ile58, Leu93, Tyr37, Phe36, Gal32, and GlcN5.
The enzyme was stable in the pH range from 5.2 to 5.7 and in the temperature range from 0 to 45°C. At pH values below 4.0 or over 7.0, the enzyme was quickly denatured. Its activity considerably decreased on lyophilization or desalting. It was completely inhibited by the detergents SDS and CTMA, but not by Brij-35 or Tween 80. The enzyme was also inactivated by urea, GlyOMe (in the presence of EDC), p-BPB, phenylglyoxal, and PMSF.
The rate of hydrolysis of Z-Glu-Phe by the enzyme increased with increasing concentration of the substrate up to 2.7×10-2M, but in the concentration range from 3.6×10-2 to 4.4×10-2M, it decreased with increasing concentration of the substrate. The values of Km and Vmax for the hydrolysis of Z-Glu-Phe were 4.0×10-2M and 2.3×10-4 mole/liter•min•mg, respectively. Inactivation of the enzyme with DFP and HgCl2 resulted in a decrease in the value of Vmax, whereas that of Km remained unchanged, indicating that DFP and HgCl2 are both noncompetitive inhibitors. β-Phenylpropionic acid, on the other hand, inhibited the enzyme reversibly and increased the value of Km without changing that of Vmax significantly, showing that the compound is a competitive inhibitor.抄録全体を表示PDF形式でダウンロード (765K) -
Role of the Substrate 2-Acetamide Group in the N-Aryl Specificity of the EnzymeKazuhiko YAMAMOTO1974 年 76 巻 2 号 p. 385-390
発行日: 1974/08/25
公開日: 2008/11/18
ジャーナル フリーThe activity of Taka-N-acetyl-β-D-glucosaminidase [EC 3. 2. 1. 30] toward fifteen newly synthesized substrate analogs with different N-substituent was determined.
The contribution of the substituent constants of the substrate N-acyl group (VW, σ*, and π) to the relative rate (VR) of enzymatic hydrolysis was evaluated quantitatively by regression analysis to ascertain the role of the substrate 2-acetamide group in the N-acyl specificity of this enzyme. The following equation gave the best fit for each parameter.
log VR=2.90-0.208VW-0.633σ*+0.538π
A mechanism for the enzymic hydrolysis was proposed based on this relationship.抄録全体を表示PDF形式でダウンロード (389K) -
Daisaku SATOMI1974 年 76 巻 2 号 p. 391-396
発行日: 1974/08/25
公開日: 2008/11/18
ジャーナル フリー1. The characteristics of ion exchange-type cation binding and ATP-dependent Ca2+ uptake in brain microsomes were investigated.
2. The accumulated Ca2+ in microsomes was exchanged for free Ca2+ in the medium continuously and the exchange occurred at nearly the same rate as initial Ca2+ uptake, even after the microsomes were saturated with Ca2+ in the presence of ATP. This exchange reaction stopped and the accumulated Ca2+ remained unaffected when ATP was depleted or when the microsomes were incubated at 0°C.
3. From the results obtained, it was concluded that ion exchange-type cation binding and ATP-dependent Ca2+ uptake occurred at different binding sites.抄録全体を表示PDF形式でダウンロード (502K) -
Its Partial Purification and Some PropertiesNoriko TOMINAGA, Takeshi MORI1974 年 76 巻 2 号 p. 397-408
発行日: 1974/08/25
公開日: 2008/11/18
ジャーナル フリーAn acid phosphatase [EC 3. 1. 3. 2] of T. thiooxidans cells hydrolyzed pNPP most rapidly at pH 2.5. The addition of sulfate ions to the reaction mixture markedly stimulated the enzyme activity and shifted the pH optimum to the neutral side with increasing concentration of sulfate.
The enzyme was solubilized and purified 360-fold with a 6% recovery. It was significantly activated by sulfate ions, with an optimum pH of 4.5 at maximum activation. The substrate specificity was found to be fairly broad and α-glycerophosphate was cleaved most rapidly among many phosphate esters tested. It was inhibited by fluoride, molybdate, inorganic phosphate, arsenate, and ascorbate. The molecular weight was estimated to be 130, 000 by the gel filtration method.抄録全体を表示PDF形式でダウンロード (915K) -
Hisashi MIYAZAKI, Keiko NAMBU, Yasuo MINAKI, Masahisa HASHIMOTO, Kiyos ...1974 年 76 巻 2 号 p. 409-417
発行日: 1974/08/25
公開日: 2008/11/18
ジャーナル フリーThe contribution of adenosine as a source of red cell nucleotides and the significance of direct phosphorylation of this nucleoside in nucleotide formation were investigated in peripheral mouse erythrocytes.
1. Radiochemical methods for the analysis of nucleotides in mouse erythrocytes were used following treatment of the cells with adenosine-u-14C. The relative significance of various metabolic pathways of adenosine in relation to nucleotide synthesis was evaluated quantitatively from the results obtained.
2. Mouse erythrocytes were incubated with adenosine-u-14C in vitro. Cells incorporated whole adenosine molecules into their nucleotide pool by direct phosphorylation and to some extent also incorporated the base moiety formed by cleavage of the nucleoside following deamination. The lower the concentration of adenosine, the more predominant was the former pathway.
3. Various amounts of adenosine-u-14C were injected intravenously into mice to get plasma concentrations of nucleoside in the range from 10-8 to 10-4M. The in vivo mode of adenosine incorporation into red cell nucleotides was found to be direct phosphorylation under the conditions employed.
4. Elimination of inosine-8-14C radioactivity from the animals after intravenous administration was faster than that of adenosine-8-14C. In intact mice, radioactivity in tissues after administration of adenosine-8-14C was higher than that after inosine-814C.
5. The results were discussed in relation to the physiological role of adenosine incorporation into the nucleotides of circulating erythrocytes.抄録全体を表示PDF形式でダウンロード (674K) -
A Possible Mechanism for Its Biphasic Effects on Cyclic AMP-dependent Lipolysis, Steroidogenesis and Amino Acid UptakeHajime IWAI1974 年 76 巻 2 号 p. 419-429
発行日: 1974/08/25
公開日: 2008/11/18
ジャーナル フリーThe effects of eritadenine isoamyl ester (EiA) on cyclic AMP (cAMP)-dependent biochemical systems were investigated in order to elucidate the mechanism of its hypolipidemic action.
EiA exhibited a twofold effect on stimulated lipolysis in rat epididymal fat cells; i.e., EiA (5×10-4M) inhibited theophylline-induced glycerol release, but potentiated the lipolytic action of epinephrine.
EiA (5×10-4M) had no effect on the theophylline-induced augmentation of cAMP levels in fat cells. EiA inhibited cAMP-dependent protein kinase [EC 2. 7. 1. 37] in the fat pad infranatant and liver supernatant fractions. Kinetic studies using partially purified liver enzyme showed that EiA inhibited protein kinase at the phosphorylation step, the inhibition being competitive with respect to ATP. EiA inhibited the cAMP phosphodiesterase [EC 3. 1. 4. 17] of fat cells. It increased the rate of cAMP accumulation in fat cells induced by epinephrine on incubation for one minute and it also potentiated cAMP-induced lipolysis.
EiA enhanced the action of lower concentrations (5×10-5M-5×10-4M) of dibutyryl-cAMP (DBcAMP) in DBcAMP-induced lipolysis, but suppressed the action of higher concentrations (10-3M) of DBcAMP. This biphasic pattern was also observed in DBcAMP-induced increase in α-aminoisobutyrate uptake by isolated perfused rat liver and in cAMP-induced steroidogenesis in rat adrenal cells. It is suggested that the biphasic effects of EiA may be due to its inhibition of both protein kinase and cAMP phosphodiesterase.抄録全体を表示PDF形式でダウンロード (808K) -
Tadahiro KOIZUMI1974 年 76 巻 2 号 p. 431-439
発行日: 1974/08/25
公開日: 2008/11/18
ジャーナル フリーTo estimate the turnovers of structural proteins of muscle, their relative rates of incorporation of five radioactive amino acids, glycine, leucine, valine, lysine, and alanine, were determined. The ratio of the turnover rates of M-protein (prepared by the method of Masaki and Takaiti (6 )): troponin:tropomyosin:α-actinin:myosin:10S-actinin:actin was approximately 7:6.5:3.3:3:2.5:1.7:1.抄録全体を表示PDF形式でダウンロード (2253K) -
Tomoh MASAKI1974 年 76 巻 2 号 p. 441-449
発行日: 1974/08/25
公開日: 2008/11/18
ジャーナル フリーThe immunochemical properties of myosins from fast white, slow red, cardiac, and smooth muscle were studied by immunodiffusion, and the fluorescent antibody techniques. Antibody against the heavy chain of each myosin generally distinguished the homologous antigen from the other three types of myosin. Antibody against the cardiac L-II light chain of myosin reacted with that of slow red fibers, but antibody against the L-II light chain of skeletal muscle myosin reacted only with the homologous protein. The reaction of the heavy chain of each myosin with its antibody could take place in the presence of sodium dodecyl sulfate.抄録全体を表示PDF形式でダウンロード (5439K) -
Kunio YAGI, Morimitsu NISHIKIMI, Akiko TAKAI, Nobuko OHISHI1974 年 76 巻 2 号 p. 451-454
発行日: 1974/08/25
公開日: 2008/11/18
ジャーナル フリーD-Amino acid oxidase [D-amino acid: O2 oxidoreductase (deaminating), EC 1. 4. 3. 3] was reduced by m- and p-methoxyphenylglycine, m- and p-methylphenylglycine, and m-chlorophenylglycine without the appearance of any long-wavelength-absorbing intermediate, as in the case of basic amino acids, though it was reduced by phenylglycine and p-chlorophenylglycine with the appearance of a long-wavelength-absorbing intermediate, as in the case of neutral amino acids. When the logarithms of the rates of reduction of the enzyme with phenylglycine derivatives, in which the enzyme was reduced without appearance of a long-wavelength-absorbing intermediate, were plotted against Hammett's σ-values, a linear correlation with a positive ρ-value was obtained in the range of σ<0. This indicates that the cleavage of the α-CH bond of the substrate by D-amino acid oxidase occurs via proton transfer prior to the reduction of the coenzyme.抄録全体を表示PDF形式でダウンロード (246K) -
Susumu OI1974 年 76 巻 2 号 p. 455-458
発行日: 1974/08/25
公開日: 2008/11/18
ジャーナル フリーPDF形式でダウンロード (245K)
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