The Journal of Biochemistry
Online ISSN : 1756-2651
Print ISSN : 0021-924X
66 巻, 3 号
選択された号の論文の19件中1~19を表示しています
  • SHIRO BANNAI, HIROSHI TERAYAMA
    1969 年 66 巻 3 号 p. 289-295
    発行日: 1969/09/25
    公開日: 2008/11/18
    ジャーナル フリー
    1. The priming (template) activities for RNA synthesis of normal and regenerating rat liver chromatins were investigated using E. coli RNA polymerase [EC 2. 7. 7. 6] and isolated chromatins. A slightly higher template activity was observed in regenerating liver chromatin but no detectable difference in the ratio of histone to DNA compared to that of normal liver chromatin.
    2. The template activities of normal and regenerating liver chromatins were com-pared after removal of different extents of histone with citric acid-NaCl. The difference in the template activities of normal and regenerating liver chromatins were still apparent up to a stage of selective removal of lysine-rich histones, but disappeared when most of the histones were removed.
    3. Removal of histones with dilute HCl caused some structural damage of the chromatins resulting in change in the template activity and melting profile.
    4. The addition of histones after their removals from chromatins inhibited template activity slightly in contrast to the dramatic increase in template activity seen on removal of histones from chromatins.
    5. The regulatory roles of histones in the synthesis of RNA are discussed on the basis of the results.
  • II. Regulation of Phosphoenolpyruvate Carboxylase and Pyruvate Kinase
    HACHIRO OZAKI, ISAMU SHIIO
    1969 年 66 巻 3 号 p. 297-311
    発行日: 1969/09/25
    公開日: 2008/11/18
    ジャーナル フリー
    Phosphoenolpyruvate carboxylase [EC 4. 1. 1. 31] and pyruvate kinase [EC 2. 7. 1. 40] were sonically extracted from Brevibacterium fiavum No. 2247, and purified to the extent of 16-fold and 30-fold, respectively, by ammonium sulfate fractionation and DEAE-cellulose column chromatography.
    Phosphoenolpyruvate carboxylase showed an optimum pH at 6.5, required Mg+ or Mn2+, and was activated by acetyl-coenzyme A and fructose 1, 6-diphosphate. The reaction rate-phosphoenolpyruvate concentration curve was sigmoid (Hill coefficient n=1.95), and the half maximal activity was attained at 3 mm phosphoenolpyruvate. In the presence of acetyl-coenzyme A or fructose 1, 6-diphosphate the curve was hyperbolic. The enzyme was specifically inhibited by L-aspartate. The curves for the reaction rate against acetyl-coenzyme A and L-aspartate were also sigmoid in the presence of L-aspar-tate and acetyl-coenzyme A.
    Pyruvate kinase showed an optimum pH at 6.5 and required Mg2+ or Mn2+, but the effect of Mg2+ was very slight. Lineweaver-Burk plots for either phosphoenolpyruvate or ADP as the variable substrate at the various fixed concentrations of ADP or phos-phoenolpyruvate, respectively, were parallel, suggesting that the pyruvate kinase reaction takes place according to a ping-pong mechanism. The enzyme is activated by AMP but not by acetyl-coenzyme A, fructose 1, 6-diphosphate and KCl. The rate-phospho-enolpyruvate concentration curve is sigmoid either in the presence or absence of AMP (Hill coefficient n was 2.0 or 3.0, respectively). Half maximal activity is attained at 0.25 mM phosphoenolpyruvate in the presence of 1 mM ADP. The curve for the reaction rate against ADP concentration is hyperbolic. ATP strongly inhibits the enzyme and this inhibition is non-competitive with respect to ADP.
    From these results, a regulation mechanism at a branching point of the glucose metabolism, phosphoenolpyruvate, is proposed.
  • CV. Conversion of 7α, 12α-Dihydroxycholest-4-en-3-one to 5α-Cyprinol by Carp Liver
    TAKAHIKO HOSHITA
    1969 年 66 巻 3 号 p. 313-319
    発行日: 1969/09/25
    公開日: 2008/11/18
    ジャーナル フリー
    The formation of 5α-cyprinol from 7α, 12α-dihydroxycholest-4-en-3-one was investi-gated in vitro with a carp liver preparation.
    1. The results indicate that a major pathway in this conversion is: 7α, 12α-dihy-droxycholest-4-en-3-one→5α-cholestane-3α, 7α, 12α-triol→deoxy-5α-cyprinol→5α-cyprinol.
    2. The microsomal fraction of carp liver catalyzed the transformation of 7α, 12α-dihydroxycholest-4-en-3-one to 5α-cholestane-3α, 7α, 12α-trios. The supernatant obtained by high speed centrifugation and the mitochondrial fraction of carp liver did not reduce this Δ4-3-keto compound to any measurable extent. The microsomal enzyme system required NADPH as a hydrogen donor and was inactive in the presence of NADH.
    3. In the presence of the microsomal fraction 5α- and 5β-cholestane-3α, 7α, 12α-triols were converted to deoxy-5α-cyprinol and 5β-cholestane-3α, 7α, 12α, 26-tetrol, respectively. The hydroxylase required NADPH as cofactor. The supernatant obtained by high speed centrifugation and the mitochondrial fraction did not catalyze the hydroxylation of these trials.
    4. The conversion of deoxy-5α-cyprinol to 5α-cyprinol was catalyzed by the mito-chondria) fraction fortified with NADPH but not by the microsomal fraction or the supernatant obtained by high 'peed centrifugation.
  • TAKEHIKO WATANABE, HIROYUKI KAGAMIYAMA, HIROSHI WADA
    1969 年 66 巻 3 号 p. 321-333
    発行日: 1969/09/25
    公開日: 2008/11/18
    ジャーナル フリー
    Studies were performed on the inhibition of aspartate transaminase [EC 2. 6. 1. 1; GOT] isozymes by their corresponding antibodies and the papain [EC 3. 4. 4. l0]-digested fragments of their respective antibodies. The inhibition produced by the fragments (FI and FII) was partially non-competitive with respect to substrates (α-ketoglutarate and aspartate). The transamination reaction between α-ketoglutarate or oxaloacetate and pyridoxamine catalyzed by apo-GOT was also strongly inhibited by the papain-digested fragments. These results suggest that the antigenic determinants are at a different locus from the active site on the GOT molecule.
    Anti-s-GOT was purified specifically by the dissociation of the antigen-antibody complex by the addition of high concentration of salt at low pH. Subsequently, the purified antibody could be separated into two types of antibodies on the basis of anti-gen-binding specificity for the suc-s-GOT molecule. One type combines with suc-s-GOT with the formation of precipitates from which it can easily be dissociated. The other type can be recovered from the supernatant solution. Both types are equally inhibitory to native s-GOT, but only that type which combines with suc-s-GOT is capable of inhibiting suc-s-GOT activity. The mechanism of the inhibition of GOT activity by antibody was discussed.
  • MICHIHIRO SUGANO, KOHJI HORI, MASAFUTO WADA
    1969 年 66 巻 3 号 p. 335-343
    発行日: 1969/09/25
    公開日: 2008/11/18
    ジャーナル フリー
    Cholesterol esterification and cholesteryl ester hydrolysis by the soluble cell fraction of the rat liver were studied in vitro.
    The extent of esterification was markedly lower than that of hydrolysis, even under conditions in which the esterification rate was considerably enhanced. When cholesterol-4-14C in plasma lipoproteins was used as a substrate, the patterns of cholesteryl-14C esters synthesized by the soluble fraction were in general similar to those formed by plasma esterification. In contrast, the 14C-esters in lipoproteins did not serve as the substrate for hydrolysis. Fasting resulted in the elevation of esterification reaction by male rats, but not females. Alterations due to fasting of the radioactivity distributions among the different esters synthesized were consistent with those of the plasma transferase. The types of cholesteryl esters synthesized in liver appear to be dependent on the nutritional status of the animal.
    Although the physiological significance of the soluble esterifying enzyme on maintenance of the level and composition of cholesteryl esters in situ is obscure, the results suggest that this enzyme possibly be the source of the plasma acyltransferase.
  • I. The Effect of Polyamines on Cell Free Polyphenylalanine Synthesis in Escherichia coli
    YOSHIFUMI TAKEDA
    1969 年 66 巻 3 号 p. 345-349
    発行日: 1969/09/25
    公開日: 2008/11/18
    ジャーナル フリー
    Replacement of magnesium ions by polyamines such as spermine, spermidine and putrescine, in polyphenylalanine synthesis by cell free preparations of Escherichia coli is described. When the concentration of magnesium ions in the reaction mixture is 5mM, no polyphenylalanine synthesis is observed. However, on addition of 0.4mM spermine alone, 3mM spermidine alone or a mixture of 0.2 mvi spermine and 1.5mM spermidine, maximum incorporation of phenylalanine into polypeptide is observed. Putrescine can also replace magnesium ions. Among the three polyamines tested, spermine is the most effective in replacing magnesium ions, followed in order by spermidine and putrescine.
  • YOSHIYUKI ICHIKAWA, TOSHIO YAMANO
    1969 年 66 巻 3 号 p. 351-360
    発行日: 1969/09/25
    公開日: 2008/11/18
    ジャーナル フリー
    NADYH-cytochrome c reductase from rabbit liver microsomes was purified to a homogeneous flavoprotein with flavin adenine dinucleotide as the prosthetic group.
    This enzyme is reduced by either NADPH or NADH and has secondary activities as transhydrogenase and diaphorase.
    The NADPH-cytochrome c reductase and diaphorase activities are inhibited by NADH.
    The Km for NADPH of the reductase activity is 3.2×10-6M and that for NADH is 1.3×10-3M. The Km for NADPH or NADH of the diaphorase activity is essentially identical with that of the reductase activity. The Km for NADPH in the enzymatic activity of transhydrogenation between NADPH to NAD+ is 6.7×10-6M and the Km for NAD+ of the transhydrogenase activity is 2.9×10-3M.
    The enzyme activity is inhibited by a series of quinoline derivatives and some other aromatic compounds in competition with NADPH. The extent of inhibition increases with increasing chain length of the alkyl substituents.
  • Brain and Pancreatic Mitochondria
    KAZUE OZAWA, OSAMU KITAMURA, TADASHI OHSAWA, TAKESHI MURATA, ICHIO HON ...
    1969 年 66 巻 3 号 p. 361-367
    発行日: 1969/09/25
    公開日: 2008/11/18
    ジャーナル フリー
    Oxidative phosphorylation of pancreatic mitochondria was found to be very labile to ischemia in vivo or aging in vitro, as is the case for brain mitochondria. Marked differences were, however, noted in the mechanism responsible for the lability in the two types of mitochondria. In pancreatic mitochondria the decrease in oxidative phos-phorylation was accompanied by a fall in the lipid acyl ester bonds and a concomitant increase in lysolecithin, probably due to the action of endogenous phospholipase A [EC 3. 1. 1. 4]. On the other hand, in a similar condition the content and composition of phospholipids in brain mitochondria did not change significantly. In brain mitochondria active incorporation of [2-14C]acetate into free fatty acids in the absence of any added cofactors was observed, but this activity was not detected in pancreatic, liver and kidney mitochondria. The possible biochemical mechanism underlying the inhibitory reaction in brain mitochondria) metabolism by ischemia or aging is discussed with particular reference to the increased pool size of endogenously synthesized free fatty acids.
  • EIJI KIMOTO, KAZUKO AKIYAMA, YOSHIAKI NOGUCHI
    1969 年 66 巻 3 号 p. 369-377
    発行日: 1969/09/25
    公開日: 2008/11/18
    ジャーナル フリー
    The antibodies, formed in rabbits after the administration of the saline-soluble substances or crude proteinpolysaccharides from human aorta, were found to be those directed toward a glycoprotein which possessed chemical and physicochemical natures similar to those of the so-called bridging protein.
    This antigenic component was eluted from DEAE-cellulose column in a relatively high quantity at the same elution volume as hyaluronic acid, migrated on electrophoresis as a diffuse band extending from α2-globulin to prealbumin zone and filtered in a void volume of Sephadex G-200 column. The antigenic component existed in a form of macromolecular aggregate of proteinpolysaccharide complexes. After the hyaluronidase [EC 3. 2. 1. 35] digestion, the antigenically reactive moiety of this complex was isolated as a glucose-containing glycoprotein with the same order of dimension as albumin.
  • KANJI TAKEO
    1969 年 66 巻 3 号 p. 379-387
    発行日: 1969/09/25
    公開日: 2008/11/18
    ジャーナル フリー
    1. It was demonstrated that an NAD-linked malic enzyme [EC 1. 1. 1.38] is present in E. coli in addition to the NADP-linked malic enzyme [EC 1. 1. 1.40]. The NAD-linked malic enzyme was purified about 100-fold and some of its properties were examined. This enzyme was different from many other malic enzymes in that it required no monovalent cation for its activity and did not undergo substrate inhibition.
    2. The apparent Km values for malate and for NAD were 9×10-4 and 4.7×10-5M, respectively, at pH 7.9. The value for Mn2+ at 10mM of malate was 1.5×10-5M, at the same pH value. It was observed that the higher the concentration of malate, the higher was the affinity for Mn2+. The optimum pH for the enzyme activity varied depending upon the concentration of malate and showed 7.5 at 0.01M malate.
    3. This enzyme showed an oxaloacetate decarboxylating activity. The optimum pH for this activity was 4.5. It was inhibited by NAD.
    4. The partially purified NADP-linked malic enzyme from E. coli was similar to those from other sources in many respects, except that it showed a full activity in the presence of adequate amounts of NH4+.
  • KEN-ICHI KASAI, TSUNEKO UCHIDA, FUJIO EGAMI, KEI-ICHI YOSHIDA, MASAO N ...
    1969 年 66 巻 3 号 p. 389-396
    発行日: 1969/09/25
    公開日: 2008/11/18
    ジャーナル フリー
  • TAKASHI MATSUBARA, YOSHIHIRO TOCHINO
    1969 年 66 巻 3 号 p. 397-404
    発行日: 1969/09/25
    公開日: 2008/11/18
    ジャーナル フリー
    Liver mitochondria from normal, alloxan-treated and pancreatectomized rats were prepared and the respiratory activities were measured polarographically. The respiratory pattern of mitochondria from diabetic animals showed more uncoupled respiration than mitochondria from normal animals. The P:O ratios and the respiratory control ratios of mitochondria from diabetic rats were lower than those of mitochondria from normal rats, but were rapidly restored to normal levels by the administration of insulin. The content of nonesterified fatty acids in the mitochondrial fraction increased in the livers of diabetic rats, and the administration of insulin decreased this elevated fatty acid level to normal.
    A possible explanation for these results is presented, with particular concern in the relation between respiratory activities in mitochondria and the effects of insulin on lipid metabolism.
  • MICHIZO SUYAMA, MICHIE MARUYAMA
    1969 年 66 巻 3 号 p. 405-407
    発行日: 1969/09/25
    公開日: 2008/11/18
    ジャーナル フリー
  • TSUTOMU NAKATA, KOICHI YAGI
    1969 年 66 巻 3 号 p. 409-412
    発行日: 1969/09/25
    公開日: 2008/11/18
    ジャーナル フリー
  • SHOSHI OTA, KUMIKO HORIE, FUSAKO HAGINO
    1969 年 66 巻 3 号 p. 413-414
    発行日: 1969/09/25
    公開日: 2008/11/18
    ジャーナル フリー
  • FUMIO SAWADA, MASACHIKA IRIE
    1969 年 66 巻 3 号 p. 415-418
    発行日: 1969/09/25
    公開日: 2008/11/18
    ジャーナル フリー
  • YOSHIO UENO, MASAKATSU HOSOYA, YOSHIYUKI ISHIKAWA
    1969 年 66 巻 3 号 p. 419-422
    発行日: 1969/09/25
    公開日: 2008/11/18
    ジャーナル フリー
  • AYAKO MATSUSHIMA, YUJI INADA, KAZUO SHIBATA
    1969 年 66 巻 3 号 p. 423-425
    発行日: 1969/09/25
    公開日: 2008/11/18
    ジャーナル フリー
  • MORIMITSU NISHIKIMI, KUNIO YAGI
    1969 年 66 巻 3 号 p. 427-429
    発行日: 1969/09/25
    公開日: 2008/11/18
    ジャーナル フリー
feedback
Top