巻号一覧
68 巻, 2 号
選択された号の論文の16件中1～16を表示しています
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Kozo OHTSUKI, Nobuko KAJIWARA, Hiroyuki HATANO1970 年 68 巻 2 号 p. 137-143
発行日: 1970/08/25
公開日: 2008/11/18
ジャーナル フリー1. Subtilisin BPN' [EC 14. 4. 16], a bacterial protease, was chemically modified with 6-diazo-l-H-tetrazole (DHT) and the nature of the modified enzyme was investigated.
2. Subtilisin modified with 19 to 60 fold molar excesses of DHT remarkably decreased its hydrolytic activity toward N-acetyl-tyrosine ethyl ester, but not so notably the activity toward casein. This effect was correlated to the modification of tyrosine residue of the enzyme.
3. Modification of one critical histidine residue by DHT brought about the inactivation of the enzymatic activities, and this inactivated enzyme failed to incorporate an irreversible inhibitor, diisopropyl phosphorofluoridate.抄録全体を表示PDF形式でダウンロード (470K) -
I. Inhibition by HydroxylamineShinya YOSHIKAWA, Yutaka ORII1970 年 68 巻 2 号 p. 145-156
発行日: 1970/08/25
公開日: 2008/11/18
ジャーナル フリー1. Unusual phenomena in the time course of the oxidation of ferrocytochrome c in the presence of cytochrome a [cytochrome oxidase, EC 1. 9. 3. 1] and hydroxylamine were studied by examining the preincubation effect of cytochrome a with hydroxyl-amine alone or with the mixture of hydroxylamine and cytochrome c under various conditions, The results indicated that the formation of the hydroxylamine-cyto-chrome a complex was not instantaneous and that the enzyme-inhibitor complex was not formed unless the enzyme reacted with the substrate in the presence of the inhibitor. It was also found that the cytochrome oxidase reaction was reversibly inhibited by hydroxylamine.
2. Based on the kinetic examination of the effect of hydroxylamine on the cyto-chrome oxidase activity and its dependence on the substrate concentration, a simple scheme which is consistent with the present results was proposed as follows; cyto-chrome a contains at least two groups, each of which is capable of combining with hydroxylamine, and the enzyme species combined with one molecule of hydroxyl-amine has a residual activity while the one combined with two molecules of hydroxyl-amine is completely inactive.抄録全体を表示PDF形式でダウンロード (3000K) -
Naotaka HAMASAKI, Toshio ASAKURA, Shigeki MINAKAMI1970 年 68 巻 2 号 p. 157-161
発行日: 1970/08/25
公開日: 2008/11/18
ジャーナル フリーGlycolysis in human red blood cells is enhanced by deoxygenation of the suspension. Accumulation of 2, 3-diphosphoglycerate is observed under this condition. Cross-over analysis of glycoiytic intermediates during the transition of red blood cells from deoxygenated to oxygenated state reveals phosphofruktokinase [EC 2. 7. 1. 11] and pyruvate kinase [EC 2. 7. 1. 40] as cross-over points. The following two mechanisms are discussed to explain the changes in the metabolic pattern: i) Release of proton by oxygenation of hemoglobin, and ii) release of 2, 3-diphosphoglycerate from hemoglobin by oxygenation. It is concluded that, under physiological conditions, the oxygen affinity for hemoglobin may be controlled by the change in 2, 3-diphosphoglycerate concentration.抄録全体を表示PDF形式でダウンロード (326K) -
Shinkichi IRIE, Tokuo ITOH, Tohru UEDA, Fujio EGAMI1970 年 68 巻 2 号 p. 163-170
発行日: 1970/08/25
公開日: 2008/11/18
ジャーナル フリー1) The pH dependence of RNase T1 [EC 2. 7. 7. 26] action on various nucleoside 2', 3'-cyclic phosphates was studied.
2) Optimum pHs for the hydrolysis of guanosine 2', 3'-cyclic phosphate, inosine 2', 3'-cyclic phosphate and xanthosine 2', 3'-cyclic phosphate by RNase T, were 7.0-7.2, 5.5-6.5 and 4.5-5.5 respectively.
3) The cleavage of 3'-xanthylyl bonds in deaminated RNA by RNase T1 was much faster at pH 5.0 than at pH 7.5, the optimum pH for RNA digestion by the enzyme.
4) The difference between the optimum pH for the cleavage of 3'-xanthylyl bond and that of 3'-guanylyl bond was discussed, especially in relation to the pKa values of the lactate form at the 1, 6-position of the purine bases.
5) Thioguanosine 2', 3'-cyclic phosphate and thioinosine 2', 3'-cyclic phosphate were quite resistant to RNase T1 in pH 4-8.抄録全体を表示PDF形式でダウンロード (509K) -
III. Effect of Purine Nucleotides on Succino-AMP Synthetase of Bacillus subtilisKenji ISHII, Isamu SHIIO1970 年 68 巻 2 号 p. 171-176
発行日: 1970/08/25
公開日: 2008/11/18
ジャーナル フリー1. Succino-AMP synthetase [EC 6. 3. 4. 4] was partially purified from the adenine starved cells of a Bacillits subtilis mutant which was derived from K strain and lacking succino-AINIP lyase [EC 4. 3. 2. 2]. The enzyme was stabilized by the presence of 1 myr dithiothreitol. Optimum pH for activity was about 7.5. Apparent Michaelis constants for IMP, GTP and L-aspartic acid were 34μM, 73μM and 680μM, respectively.
2. The enzyme was inhibited strongly by the end products, AMP and ADP. Complete inhibition was obtained by 0.3 mM AMP. The inhibition by AMP was competitive to GTP, noncompetitive to L-aspartic acid and of a miffed type to IMP. Both the Lineweaver-Burk plots in the presence of AMP and rate-AMP concentration curve were normal. Succino-AMP, GDP and inorganic orthophosphate, which are the direct product of the reaction, were also inhibitory at higher concentrations.抄録全体を表示PDF形式でダウンロード (1130K) -
Katsuko KAKINUMA1970 年 68 巻 2 号 p. 177-185
発行日: 1970/08/25
公開日: 2008/11/18
ジャーナル フリー1) Significant increase in lactate production was observed within 5 min of phagocytosis by leucocytes. 2) Intracellular concentrations of glycolytic intermediates and cofactors were measured at different incubation intervals in order to know about the mechanism controling the glycolytic activity during phagocytosis. 3) Fructose 1, 6-diphosphate tended to decrease within 5 to 10 min of incubation after adding bacteria. 4) According to the 5, 5-dimethyl-2, 4-oxazolidinedione method, it has been found that intracellular pH decreased in the same interval of phagocytosis. 5) A correlation between intracellular pH and glycolytic activity was discussed.抄録全体を表示PDF形式でダウンロード (665K) -
II. DNA-Cellulose Chromatography of Antibiotics and Related CompoundsAkiyo INAGAKI, Makoto KAGEYAMA1970 年 68 巻 2 号 p. 187-192
発行日: 1970/08/25
公開日: 2008/11/18
ジャーナル フリーThe interactions of some antibiotics and basic dyes to DNA were studied by the DNA-cellulose column chromatography. Dihydrostreptomycin and methyl green were retained by the DNA column and were dissociated by increasing the NaCl concentration in the eluent. Acridine orange was not recovered from the column with NaCl up to 2M, but was eluted out by the addition of urea in the eluent. Actinomycin D was separated in two peaks by this chromatography, a fraction recovered with NaCl only and a fraction dissociated with 2M NaCl and urea. Chromomyein A3 was not retained by the column in the absence of Mg2+. But in the presence of Mg2+, this drug showed a very strong association to DNA which was not dissolved with NaCl and urea. The nature of the interaction of these materials was discussed.抄録全体を表示PDF形式でダウンロード (431K) -
Yuji INADA, Ayako MATSUSHIMA, Izumi KOTOKU, Syed Akhter HOSSAIN, Kazuo ...1970 年 68 巻 2 号 p. 193-198
発行日: 1970/08/25
公開日: 2008/11/18
ジャーナル フリーEquine thrombin was obtained in a homogeneous state from prothrombin by activation with tri-sodium citrate, followed by gel filtration through a Sephadex G-100 column and by chromatography with DEAE cellulose. This preparation was shown to be chromatographically homogeneous and the homogeneity was further confirmed by electrophoresis and by ultracentrifugal analysis. The sedimentation and diffusion constants, s020, W and D°20, W, and the partial specific volume were determined to be 3.87S, 8.66×10-7cm2/sec and 0.686 ml/g, respectively, from which the molecular weight and frictional ratio were calculated to be 34, 600 and 1.16, respectively. The esterase activity of equine thrombin as measured with TAMe as the substrate was 1.7×10-5 mole/ min/mg of protein, and the Michaelis constant (Km) was 2.36×10-4M. The amino acid contents were determined by a common procedure of amino acid analysis. The content of glutamic acid including its amide was lower than that in bovine thrombin, whereas the content of isoleucine was higher. The contents of other amino acids were similar to those reported for bovine thrombin. The sum of the amino acid contents was 263±12 residues per mole, from which the molecular weight was calculated to be 30, 700±1, 200. The about 10% difference between the molecular weight calculated from the amino acid contents and that determined by sedimentation-diffu-sion analysis is due to the content of sugars assumed in the calculation of the amino acid contents. The content of hexose in equine thrombin was 3.7%.抄録全体を表示PDF形式でダウンロード (1217K) -
Hiromichi OKUDA, Ikuko YANAGI, Frank J. SEK, Setsuro FUJII1970 年 68 巻 2 号 p. 199-203
発行日: 1970/08/25
公開日: 2008/11/18
ジャーナル フリーActivity of rat epididymal adipose tissue lipase was significantly influenced according to the way of its expression. When the activity was expressed as μEq per g of tissue, the lipase activity of the tissue of starved rats was higher than that of the tissue of fed rats. On the other hand, when expressed as μEq per mg of protein, the lipase activity of starved rats was lower than that of the tissue of fed rats. Though adrenaline increased the release of free fatty acids from adipose tissue slice, the lipase activity was not activated by this hormone. Our cell free system, in which adrenaline stimulated lipolysis, was compared with Rizack's system. Though remarkable activation was observed in our system, there was no significant stimulation of lipolysis by adrenaline in Rizack's system.
Dichloroisoproterenol considerably inhibited the stimulation of lipolysis by adrenaline in our cell free system as well as in the slice system.
These results support our previous conclusion that there is no hormone-sensitive lipase in adipose tissue.抄録全体を表示PDF形式でダウンロード (380K) -
Keitaro HIROMI, Toshio SHIBAOKA, Sôzaburo ONO1970 年 68 巻 2 号 p. 205-214
発行日: 1970/08/25
公開日: 2008/11/18
ジャーナル フリー1. The kinetics of the complex formation between iodine-iodide and amyloses of various number-average degrees of polymerization (DPn) at large excess of amylose was studied by stopped-flow method, over the wavelength range of 280-800mμ, at pH 4.9 and 24.7°C.
2. With amyloses of DPn=15 and 28, the reaction was found to be completed within about 1 msec, the dead-time of the apparatus. However, with amyloses of DPn above about 40, at least two stages with considerably different velocities were observed.
3. A typical example with amylose of DPn=8, 700 and at low iodine concentration showed that the spectral change which was developed within the dead-time had an absorption peak around 570 mμ, while that developed in the first stage which was observable by the stopped-flow method (stage C) had a peak at longer wavelength around 660 mμ. Most of the free triiodide ions have been taken up within the deadtime.
4. The time course of stage C followed apparent first-order kinetics, and the first-order rate constant, k, of this stage was roughly proportional to the fifth power of added iodine concentration, (I2)0, at lower (I2)0 range, and tended to saturate at higher (I2)0. k was almost independent of amylose concentration over the range studied (0.0025-0.1%). At fixed concentration of added iodine, k increased with about the fifth power of DPn up to DPn_??_140, above which it was independent of DPn of amylose.
5. These results are essentially consistent with a simplified mechanism, in which a complex with shorter poly-iodine chain is formed rapidly and reversibly within the dead-time about 1 cosec and this complex subsequently transforms into a complex with loner poly-iodine chain without appreciable participation of free triiodide ion in solution. The latter change is considered to correspond to stage C.
6. Evidence has been obtained which indicated that stages following stage C may involve the rearrangement of poly-iodine chain once formed in stage C into a thermodynamically more stable state, which could have shorter poly-iodine chain than that involved in stage C.抄録全体を表示PDF形式でダウンロード (3733K) -
Katsura IZUI, Tsukasa NISHIKIDO, Kanji ISHIHARA, Hirohiko KATSUKI1970 年 68 巻 2 号 p. 215-226
発行日: 1970/08/25
公開日: 2008/11/18
ジャーナル フリーWith partially purified phosphoenolpyruvate (PEP) carboxylase [EC 4. 1. 1. 31] of Eschcrichia coli W, the following observations were made which suggest the presence of an allosteric regulatory site on the enzyme for binding with L-aspartate, an inhibitor of the enzyme: (i) The enzyme was specifically protected by aspartate against heat inactivation. (ii) Oxaloacetate, the reaction product, showed only a slight inhibition, suggesting that aspartate exerts its action not as an analogue of oxaloacetate. (iii) The sensitivity of the enzyme to aspartate was shown not to be inherent in all PEP carboxylases from the fact that the enzymes from other organisms such as spinach leaves and Thiobacillus thiooxidans were not inhibited by aspartate.
Activation by fructose 1, 6-diphosphate (FDP) was confirmed with the E. coli enzyme and the effect of FDP on the enzyme affinity for PEP and on the inhibition by aspartate was studied.
Activation by cyclohexylammonium ions were confirmed and discussion was made on the “pseudo-cooperativity of PEP” which was observed when cyclohexylam-monium PEP was employed as substrate.
Strong inhibition by chloride ions was found and the effect of the ions on the activation by CoASAc was studied.抄録全体を表示PDF形式でダウンロード (895K) -
Katsura IZUI1970 年 68 巻 2 号 p. 227-238
発行日: 1970/08/25
公開日: 2008/11/18
ジャーナル フリーPhosphoenolpyruvate (PEP) carboxylase from Escherichia coli is an allosteric enzyme which is activated by CoASAc or fructose 1, 6-diphosphate and inhibited by L-aspartate. The effect of CoASAc and aspartate on kinetic properties of the enxyme was extensively studied.
1. Among the three reaction components (PEP, HCO3- and Mg2+), PEP was the only component, the kinetic properties of which were remarkably affected by the effectors.
2. CoASAc increased the affinity of the emzyme for PEP and increased Vmax attainable at the infinite concentration of PEP. On the other hand, aspartate decreased the affinity for PEP but caused no effect on Vmax. Therefore, it became clear that the effect of CoASAc and aspartate is not just antipodal to one another, though apparently they are antagonistic.
3. The shape of PEP-saturation curve was not sigmoidal in the absence of the effector (Hill's coefficient, n=1.1), but, curiously, the sigmoidicity increased signifi-cantly with increasing concentrations of CoASAc in a range of concentrations of 0-0.05mM (n=1.1-1.6). By further addition of CoASAc (0.1mM), it decreased to 1.3. When aspartate (2.5mM) was added to the reaction mixture which contained CoASAc 0.5mM), the curve was again converted to remarkably sigmoidal one (n-2.5).
4. With increasing concentrations of PEP the affinity for CoASAc increased and the shape of CoASAc-saturation curve was converted from sigmoidal to hyperbolic one. The addition of aspartate decreased the affinity for CoASAc and increased the sigmoidicity of CoASAc-saturation curve. The quantitative investigation of the CoASAc concentrations requried for compensating the inhibition caused by various concentrations of aspartate, revealed that the order of aspartate action was apparently higher than that of CoASAc action.
5. The three-state model was presented for this enzyme to explain the kinetic features described in the present and previous reports (Biochim. Biophys. Acta, 139, 188 (1967)).抄録全体を表示PDF形式でダウンロード (866K) -
Takashi MURACHI, Tokiko MIYAKE, Nobuyuki YAMASAKI1970 年 68 巻 2 号 p. 239-244
発行日: 1970/08/25
公開日: 2008/11/18
ジャーナル フリーHen egg-white lysozyme [EC. 3. 2. 1. 17] was allowed to react with a 309-fold molar excess of diisopropylphosphorofluoridate (DFP) at 25°C and at pH values ranging from 9.5 to 11.0, for 3 hr. The enzyme protein was recovered from the reaction mixture and analyzed for phosphorus content, number of ionizable phenolic hydroxyl groups, and enzymatic activities. The data obtained indicate that lysozyme is diisopropyl-phosphorylated to various extents depending upon the pH value used. The alkyl-phosphorylated enzyme preparations, compared to the unmodified lysozyme, retain full activity on glycol chitin, and also catalyze the hydrolysis of p-nitrophenyl acetate at an almost unaltered rate; but they show 20 to 25% decrease in lytic activity on Micrococcrus lvsodeikticrus cells. The phosphorylated lysozyme preparation shows a decrease in number of ionizable phenolic hydroxyl groups per molecule of protein, indicating that the modification has occurred at tyrosyl residues. Alkylphosphorylation of some amino acid residues other than tyrosine is also suggested. In the presence of saturating concentration of DFP, the modification reaction of lysozyme at a given pH value between 10.0 and 11.2 follows the first-order kinetics with respect to the concentration of the reacting tyrosyl residues at that pH. The latter concentration is most likely related to the degree of phenolic ionization of these residues.抄録全体を表示PDF形式でダウンロード (445K) -
Tomoo NOGUCHI, Hiroki KASEDA, Ryo KIDO, Yuichi MATSUMURA1970 年 68 巻 2 号 p. 245-247
発行日: 1970/08/25
公開日: 2008/11/18
ジャーナル フリーPDF形式でダウンロード (181K) -
Kenji TAKAHASHI1970 年 68 巻 2 号 p. 249-251
発行日: 1970/08/25
公開日: 2008/11/18
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Haruki YAMAGUCHI, Tokuji IKENAKA, Yoshio MATSUSHIMA1970 年 68 巻 2 号 p. 253-254
発行日: 1970/08/25
公開日: 2008/11/18
ジャーナル フリーPDF形式でダウンロード (141K)
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