巻号一覧
72 巻, 2 号
選択された号の論文の28件中1～28を表示しています
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III. Kinetics of Allosteric InteractionsMasataka YOSHINO, Nobuaki OGASAWARA1972 年 72 巻 2 号 p. 223-233
発行日: 1972/08/25
公開日: 2008/11/18
ジャーナル フリーThe allosteric properties of AMP nucleosidase [EC 3. 2. 2. 4] from A. vinelandii have
been qualitatively and quantitatively accounted for by the concerted transition theory proposed by Monod, Wyman, and Changeux, assuming that this enzyme is composed of both of “V system” and “K system.” On the basis of these assumption, AMP nucleosidase is considered to have three conformational states (I, R, and T), which differ in their dissociation constants for various ligands.
ATP is an allosteric activator in the V system, which has lower affinity for I state (inactive) and a higher affinity for the R state (active), while Pi has a higher affinity for the I state. The enzyme is likely to have four sites for ATP and Pi, respectively. AMP has the same affinity for the I and R states. GMP and IMP are inhibitors which have high affinities for the T state, while no or little affinity for the R state. Both ATP and AMP have extremely low affinities for the T state. AMP and GMP have also four sites for this enzyme. Pi decreases the cooperativity of GMP inhibition, suggesting the preferential binding of Pi to the T state in the presence of GMP.
In view of these results, the physiological significance of AMP nucleosidase in regulation of purine nucleotides metabolism was discussed.抄録全体を表示PDF形式でダウンロード (738K) -
I. Effect of Pronase, a Protease Preparation from Streptomyces griseus, on Glucose Uptake by Mouse DiaphragmYukiho KUBOTA, Hiroshi UEKI, Shozo SHOJI1972 年 72 巻 2 号 p. 235-241
発行日: 1972/08/25
公開日: 2008/11/18
ジャーナル フリーAn attempt was made to establish a method for in vitro assay of insulin-like activity of proteases by using two hemidiaphragms from dd mice. Pronase, a protease preparation from Streptomyces griseus, was found to show an insulin-like effect on glucose uptake by hemidiaphragm by using this method. At high concentrations of the enzyme, this effect was reduced because of the destruction of diaphragm tissue, and an inverse relationship was observed between insulin-like activity and diaphragm tissue-digesting activity. Preincubation of Pronase at pH1.4 or 12.0 destroyed the bulk of its proteolytic activity, whereas its stimulatory effect on glucose uptake was remarkable, suggesting the independency of the two activities from one another. The possibility that the increase in glucose uptake is responsible for the proteolytic activity, however, is not completely excluded at the present stage.抄録全体を表示PDF形式でダウンロード (504K) -
II. Effect of Magnesium Ion on Uncoupled MitochondriaTsukasa SUGANO, Yuzo NAKASE, Takeshi TSUJIMOTO, Otoji NAGAI1972 年 72 巻 2 号 p. 243-250
発行日: 1972/08/25
公開日: 2008/11/18
ジャーナル フリーThe effect of Mg2+ on substrate oxidation in rat brain mitochondria was studied in the presence and absence of reagents affecting the electron transport system or the energy-transfer system. With succinate as substrate (in the absence of rotenone), addition of 2, 4-dinitrophenol cause a brief increase in the rate of respiration, followed by inhibition (secondary inhibition). This inhibition of brain mitochondria was like that of liver mitochondria, but occurred at lower concentrations of 2, 4-dinitrophenol. With glutamate as substrate, the secondary inhibition was not observed. The addition of 2, 4-dinitrophenol at concentrations higher than a critical level (50μM) resulted in less prominent respiratory release. The inhibition of uncoupled respiration by higher concentrations of 2, 4-dinitrophenol (primary inhibition) was observed with either succinate (± rotenone) or glutamate, and was overcome by raising the substrate concentration. Mg2+ did not influence the secondary inhibition, but stimulated mitochondria during the primary inhibition. Phosphate was not required for this effect of Mg2+. The presence of Mg2+ enhanced the substrate accumulation in mitochondria irrespective of the presence or absence of uncouplers, preloaded ATP or respiratory inhibitors. From these results, it is suggested that Mg2+, like K+ exerts a direct stimulatory effect on the penetration of substrates into brain mitochondria in various metabolic states, thus counteracting the inhibition of substrate penetration caused by 2, 4-dinitrophenol.抄録全体を表示PDF形式でダウンロード (554K) -
III. Distribution of Xanthurenic Acid and Formation of Xanthurenic Acid-Insulin Complex in SerumEdahiko MURAKAMI, Yahito KOTAKE1972 年 72 巻 2 号 p. 251-259
発行日: 1972/08/25
公開日: 2008/11/18
ジャーナル フリーThe distribution of added xanthurenic acid (XA) in the serum was studied by in vitro experiments with unlabeled and tritium labeled XA, both with healthy and diabetic serum, with and without added insulin. From this experiment it was elucidated that XA binds to both albumin and insulin fractions. The amounts of XA bound to the serum protein are larger in a normal serum than a diabetic serum. The distribution of 131I-insulin in the serum was also studied. To elucidate the binding of XA to insulin, tritium labeled XA was injected to the rat and the sera were subjected to chromatography on the Sephadex column after it was treated with anti-insulin serum. The distribution of 3H-XA was checked in eluates. The result shows that injected 3H-XA binds to the circulating insulin and the resulting complex combines to the anti-insulin serum. Thus, we can confirm the binding of XA with insulin in the serum.抄録全体を表示PDF形式でダウンロード (563K) -
Koichi TAMOTO, Tohoru NAKAMURA, Jiro KOYAMA1972 年 72 巻 2 号 p. 261-268
発行日: 1972/08/25
公開日: 2008/11/18
ジャーナル フリーAs reported in a previous paper (1), both of guinea pig 7S γ1 and 7S γ2-antibodies to ovalbumin contained non-precipitating antibodies. In the quantitative precipitin reaction, two preparations of purified 7S γ2-antibodies so far tested showed weak precipitability and 40 and 50 percent of their antibodies could not precipitate with ovalbumin.
By gel-filtration of supernatants which were obtained by quantitative precipitin reactions at the maximum precipitation, it was found that most of the antibodies in the supernatants remained free and only small amounts of soluble antigen-antibody complexes were detected. These non-precipitating 7S γ2-antibodies, when isolated, could not form any insoluble complex with antigen. They could not also fix guinea pig complement, whereas their passive hemaglutinating activities were of the same order of magnitude as those of the precipitating 7S γ2-antibodies. These observations indicated that the non-precipitating antibodies were incapable of forming latticework of antigen-antibody complexes.
These results suggested that the non-precipitating 7S γ2-antibodies belonged to an antibody population which reacted with some particular antigenic determinant on ovalbumin and were produced in excess, as compared with other populations of antibodies.抄録全体を表示PDF形式でダウンロード (577K) -
Junjiro MATSUMOTO, Sadamu NAGAI1972 年 72 巻 2 号 p. 269-279
発行日: 1972/08/25
公開日: 2008/11/18
ジャーナル フリーTwo aminoacylases [EC 3. 5. 1] from Mycobacterium smegmatis were purified as single protein components, based on analysis by ultracentrifugation and electrophoresis.
The enzyme, “short acyl aminoacylase” which exhibited hydrolytic activity toward N-short chain fatty acyl amino acids, had a sedimentation coefficient s20, w=5.83S and a molecular weight of 88, 000 or 90, 000 as determined by the method of Archibald or by gel filtration, respectively. Another enzyme, “long acyl aminoacylase, ” exhibited hydrolytic activity toward N-long chain fatty acyl amino acids, was found in a soluble state in extracts from Mycobacteria. It had a sedimentation
coefficient s20, w=4.74S and a molecular weight of 40, 000 or 48, 000 as determined by the procedures described above.
Other properties of the enzymes which were studied were optical specificity, stoichiometry, activation, and inhibition. In these studies acetyl-amino acids and palmitoyl-amino acids were used as the substrates for short and long acyl aminoacylases, respectively.抄録全体を表示PDF形式でダウンロード (1482K) -
Hiroyasu NAKATA, Shin-ichi ISHII1972 年 72 巻 2 号 p. 281-290
発行日: 1972/08/25
公開日: 2008/11/18
ジャーナル フリーThe initial rates of hydrolysis of α-N-benzoyl-L-arginine p-nitroanilide catalyzed by bovine trypsin [EC 3. 4. 4. 4] were examined with a wide range of substrate concentrations. The rates at high substrate concentrations were found to be exceedingly higher than those expected from the simple Michaelis-Menten equation which seemed applicable at the lower concentration. The phenomenon is observed not only with the commercial enzyme preparation but also with isolated α-or β-trypsin. The kinetics can be fitted to the substrate activation scheme, which has been proposed by Trowbridge et al. to account for their findings on a similar anomalous behavior of trypsin with α-N-tosyl-L-arginine methyl ester as substrate.
The activity of trypsin toward the same nitroanilide substrate is enhanced significantly by acetylation of the enzyme, especially on its tyrosyl residues with acetylimidazole. The enhancement is prominent only at the low substrate concentration. The acetylation of trypsin has been reported to intensify the activity toward α-N-tosyl-L-arginine methyl ester only at high substrate concentrations and to amplify the substrate activation in the enzyme. The striking contrast observed between the two substrates may reflect the difference in the rate limiting step of their hydrolyses catalyzed by trypsin.抄録全体を表示PDF形式でダウンロード (714K) -
II. Purification of NAD-independent Glycerolphosphate Dehydrogenase Bound to Minute Particles from Supernatant Fraction of Propionibacterium arabinosumNobuhito SONE, Shin KITSUTANI1972 年 72 巻 2 号 p. 291-297
発行日: 1972/08/25
公開日: 2008/11/18
ジャーナル フリーNAD-independent glycerol-P dehydrogenase [EC 1. 1. 99. 5] from P. arabinosum cells, found in the supernatant fraction of the centrifugation at 104, 000×g was tried to purify. After 22-fold purification, the dehydrogenase preparation oxidized 7.5μmoles of glycerol-P with DCIP per min per mg protein. The behavior of the enzyme during purification, electron microscopic observation, and a low density of the partially purified sample owing to a high phospholipid content strongly suggest that glycerol-Pdehydrogenase was located minute membrane fragment-like particles. This particulate preparation of glycerol-P dehydrogenase exhibited lactate dehydrogenase [EC 1. 1. 2. 4] activity but scarcely did other activities occasionary found in membranes, such as those of NADH dehydrogenase [EC 1. 6. 99. 3], and succinate dehydrogenase [EC 1. 3. 99. 1], and ATPase [EC 3. 6. 1. 3]. Relationship of this glycerol-P dehydrogenase particles to the bacterial membrane was discussed.抄録全体を表示PDF形式でダウンロード (2195K) -
I. Tryptic Peptides of Succinylated and Unmodified HistoneKatsutoshi ISHIKAWA, Hiroaki HAYASHI, Koichi IWAI1972 年 72 巻 2 号 p. 299-326
発行日: 1972/08/25
公開日: 2008/11/18
ジャーナル フリーLarge scale preparation of calf thymus historic rich in lysine and serine in a homogeneous form was achieved by chromatography. Amino acid analysis showed that it had the following composition (in molar ratios): Lys20Arg8His3Asp6Glu10Ser13(14) Thr8Pro6Gly7Ala13Val9Met1.4(2)Ile6Leu6Phe2Tyr3.8(5) in agreement with the sequence analysis except for Ser, Met, and Tyr. No modified amino acids were found. For the total of 125 residues, a molecular weight of 13, 775 was calculated. Tryptic hydrolysis was performed both with lysine-blocked (ε-N-succinylated) and unblocked histone. The resulting peptide mixtures were separated quantitatively and purified by repeated column chromatographies, and their sequences were determined quantitatively by standard methods. In all 23 peptides, each consisting of 2 to 15 amino acid residues, were obtained from the unblocked histone in yields of 4 to 77%, together with free lysine and arginine, and 13 peptides, each consisting of 2 to 30 residues, were derived from the blocked histone in yields of 2 to 72%. They each accounted for all the amino acids of this histone. Three large peptides from the blocked histone served to identify which peptides from the unblocked histone were present in the N- and C-terminal regions and in internal regions. In this way the complete or partial sequences in nine regions of the whole molecule were determined.抄録全体を表示PDF形式でダウンロード (1555K) -
II. Chymotryptic and Thermolysin PeptidesHiroaki HAYASHI, Koichi IWAI1972 年 72 巻 2 号 p. 327-356
発行日: 1972/08/25
公開日: 2008/11/18
ジャーナル フリーThe calf thymus histone rich in lysine and serine was hydrolyzed with chymotrypsin and thermolysin for the sequence determination. The thermolysin digestion was examined in various ratios of enzyme to histone and at various pH's for optimum use of the enzyme. The resulting peptide mixtures were quantitatively separated and purified by repeated column chromatographies, and they were sequenced by quantitative standard methods together with the selective tritiation method for the C-terminal analysis. Thus 27 peptides consisting of 2 to 15 amino acid residues were obtained in yields of 11 to 75% from the one and three hour chymotryptic digests, and 35 peptides consisting of 2 to 21 residues were obtained in yields of 8 to 95% from the thermolysin digests under the optimum conditions. Both the peptides revealed the complete or partial sequences both in 19 regions of the whole molecule, respectively, each accounting for all the 125 amino acids of this histone. Chymotrypsin cleaved particular lysyl and arginyl bonds, but thermolysin never cleaved any bonds involving the amino groups of basic residues as expected.抄録全体を表示PDF形式でダウンロード (1487K) -
III. Complete Amino Acid Sequence and Its Implication for Interactions of Histones with DNAKoichi IWAI, Hiroaki HAYASHI, Katsutoshi ISHIKAWA1972 年 72 巻 2 号 p. 357-367
発行日: 1972/08/25
公開日: 2008/11/18
ジャーナル フリーThe complete sequence of 125 ammo acid residues (molecular weight, 13, 775) in the calf thymus histone rich in lysine and serine was established by overlapping into a unique sequence of the complete or partial sequences of tryptic, chymotryptic, and thermolysin peptides revealed in the preceding papers. This complete sequence was further confirmed by analyses for the N- and C-terminal sequences, and especially by fragmentation at two rnethionine residues with cyanogen bromide. The established sequence was characterized in comparison with one complete and two partial sequences of other types of histone. Thus it was revealed as characteristics common to the histone sequences that either terminal region (N-terminal in this case) is the most enriched in basic amino acids and proline with characteristic clustering of basic residues and short spacing between them, whereas the other regions are enriched in hydrophobic, acidic, and hydroxyamino acids with depletion in basic residues and long spacing between them. Based on these common features of the various sequences and the reported conformational changes of this and other histones, a molecular model of histone-DNA complex was proposed which illustrates the composition and structure of native deoxyribonucleoprotein and indicates the mechanisms responsible for constraining the DNA into superhelix and thus regulating its template activity for RNA synthesis.抄録全体を表示PDF形式でダウンロード (1613K) -
Iwao OHTSUKI, Takeyuki WAKABAYASHI1972 年 72 巻 2 号 p. 369-377
発行日: 1972/08/25
公開日: 2008/11/18
ジャーナル フリー1. In order to clarify the structure of paracrystals of actin (Hanson, 1967) and two types of paracrystals made of troponin-tropomyosin-actin complex, electron micrographs of negatively stained specimens of these paracrystals were studied by optical diffraction and optical filtering methods.
2. The actin paracrystal consists of parallel arrays of actin filaments. The filaments align in register along the filament axis, being in contact with each other at the portions between the crossover points of double strands.
3. The first type of paracrystal made of troponin-tropomyosin-actin complex shows essentially the same arrangement of actin filaments as that in the actin paracrystal.
4. The second type of troponin-tropomyosin-actin paracrystal shows clear regular transverse striations of about 380 Â period, which seem to be made of troponin molecules. The period corresponds to the length of seven actin molecules. The actin subunits of neighboring filaments are not in register.
5. The structure of troponin-tropomyosin-actin filament was discussed.抄録全体を表示PDF形式でダウンロード (3147K) -
II. Purification and Some Properties of Two Types of Staphylolytic Enzymes from Streptomyces griseusTadashi YOSHIMOTO, Daisuke TSURU1972 年 72 巻 2 号 p. 379-390
発行日: 1972/08/25
公開日: 2008/11/18
ジャーナル フリーA strain belonging to Streptomyces was found to produce two types of lytic enzymes active toward Staphylococcus aureus. Both staphylolytic enzymes were highly purified by fractionation with ammonium sulfate, column chromatography on Duolite A-2 and CM-cellulose and by isoelectric focusing method. They were named Fl and F2 lytic enzymes, respectively. Fl lytic enzyme was active toward whole cells of S. aureus, Aerobacter cloacae, Bacillus freudenreichii, and Proteus vulgaris, but was completely inert against Micrococcus lysodeikticus. Casein was also a good substrate of the enzyme. Liberation of amino groups from cell walls of S. aureus by incubation with Fl lytic enzyme suggests that the enzyme is a kind of cell wall lytic peptidase [EC Class 3. 4. 4]. F2 lytic enzyme lyzed whole cells of the genus Bacillus as well as of S. aureus but did not attack M. lysodeikticus. Liberation of reducing sugars from cell walls of S. aureus by incubation with F2 lytic enzyme suggests it to be a kind of lysozyme [EC 3. 2. 1. 17]. From taxonomic analysis, the strain used here was identified belonging to Streptomyces griseus.抄録全体を表示PDF形式でダウンロード (1455K) -
Shin-ichiro EJIRI, Hideharu TAIRA, Kensuke SHIMURA1972 年 72 巻 2 号 p. 391-401
発行日: 1972/08/25
公開日: 2008/11/18
ジャーナル フリー1. Three factors (amino acid polymerase (APase) I, APase II and G-factor) which were required for the incorporation of amino acid moiety from amino-acyl-tRNA into protein were prepared from the supernatant fraction of posterior silk gland of silkworm, Bombyx mori, L.
2. Optimum conditions for the incorporation of 14C-glycine from 14C-Gly-tRNA were pH 7.4, 5-10mM MgCl2, 150mM KCl or NH4C1, 5mM β-mercaptoethanol and 0.4mM of GTP.
3. The incorporation reaction was inhibited by fusidic acid, puromycin, blasticidin S, cycloheximide, pancreatic ribonuclease [EC 2. 7. 7.16], and diphtheria toxin in the presence of NAD+.
4. APase II was inhibited by N-ethylmaleimide, whereas APase I was not.
5. APase I was interchangeable with rat liver transferase I, and APase II with transferase II, respectively. On the contrary, the three factors from the silk gland were completely inactive when they were combined with an E. coli ribosome system.
6. The protein synthesized in the present cell-free system has been proved to be mainly fibroin.抄録全体を表示PDF形式でダウンロード (734K) -
Shin-ichiro EJIRI, Hideharu TAIRA, Kensuke SHIMURA1972 年 72 巻 2 号 p. 403-409
発行日: 1972/08/25
公開日: 2008/11/18
ジャーナル フリー1. Among the three factors (amino acid polymerase (APase) I, APase II, and G-factor) required for fibroin biosynthesis in a cell-free silk gland system, APase I was shown to concern with the binding of amino-acyl-tRNA to ribosomes.
2. The APase I-dependent binding reaction was demonstrated to require GTP and reach the maximum level of the reaction at 5.0×lO-6M GTP.
3. GMP-PCP (β-γ-methylene analogue of GTP) could substitute for GTP in the binding reaction.
4. At 5mM MgCl2, the binding of 14C-Gly-tRNA to silk gland ribosomes was completely dependent on the presence of APase I, but at higher concentrations of MgCl2 than 10mM, non-enzymatic binding was observed.
5. The ratios of the amounts of each amino-acyl-tRNA bound to posterior- or middle silk gland ribosomes were proportional to those of the contents of corresponding amino acids in fibroin and sericin, respectively.抄録全体を表示PDF形式でダウンロード (499K) -
Kazuhiko WAKABASHI, Toshiaki TAKAHASHI, Kiyozo KAWAI, Kazushige HIROSA ...1972 年 72 巻 2 号 p. 411-416
発行日: 1972/08/25
公開日: 2008/11/18
ジャーナル フリーA nuclear petite was isolated from a haploid yeast by treatment with nitrosoguanidine. The gene involved in this mutant was demonstrated to be a single nuclear gene. This mutant possessed stable ρ factor and it segregated spontaneous ρ- cells at about 1%.
It contained a normal amount of cytochrome c and a small amount of b- and a-type cytochromes. ATPase [ATP phosphohydrolase, EC 3. 6. 1. 3] in this mutant was cold stable and sensitive to oligomycin. It was similar to mitochondrial ATPase and electron-microscopic study revealed knobs attached to the membrane, but it differed from the mitochondrial ATPase in terms of pH dependency.抄録全体を表示PDF形式でダウンロード (1247K) -
VII. Recognition and Release of Ca2+ IonsShinpei YAMADA, Yuji TONOMURA1972 年 72 巻 2 号 p. 417-425
発行日: 1972/08/25
公開日: 2008/11/18
ジャーナル フリーCa2+-Mg2+-dependent ATPase [EC 3. 6. 1. 3] was prepared from the SR by salt fractionation after solubilization of the SR by treatment with DOC. The affinities of the enzyme for Ca2+ and Mg2+ ions during the formation and decomposition of a phosphorylated intermediate (EP) were determined at an ionic strength of 0.16 at pH 7.0 and 0°C. The following results were obtained.
1. The formation of EP required Ca2+ ions and was inhibited by Mg2+ ions which competed with Ca2+. The effects of Ca2+ and Mg2+ ions on the rate of EP-formation, vf, were expressed as
_??_
The values of KCa, KMg, and Vf were found to be 0.35μM, 10.6mM, and 1.33mole/106 g•sec, respectively.
2. The decomposition of EP required Mg2+ ions and was inhibited by Ca2+ ions, which competed with Mg2+. The effects of Mg2+ and Ca2+ ions on the rate of EP-decomposition, vo/[EP], were given by
_??_
where vo and [EP] are the rate of ATP-hydrolysis and the concentration of EP at the steady state, respectively. The values of KMg/KCa, and kd were found to be 2.45 and 0.12 sec-1, respectively.
These two results show that the affinities of the enzyme for Ca2+ and Mg2+ ions change dramatically during EP-formation.
3. The Ca2+ ions required for EP-formation could be replaced by Sr2+ ions, but the Mg2+ ions required for EP-decomposition could not be replaced by other cations, such as Mn2+, Zn2+, La3+, and Ce3+.抄録全体を表示PDF形式でダウンロード (581K) -
Akira INOUE, Daisaburo FUJIMOTO1972 年 72 巻 2 号 p. 427-431
発行日: 1972/08/25
公開日: 2008/11/18
ジャーナル フリーPrevious studies demonstrated the presence of histone deacetylase, an enzyme which released 14C-acetate from 14C-acetate-labeled histones, in an extract of calf thymus. This paper is concerned with the substrate specificity of the enzyme. In agreement with the observations by Vidali et al. (J. Biol. Chem., 243, 6361 (1968)), 14C-acetyl groups in the substrate histones prepared by incubating the calf thymus nuclei with 14C-acetate were mainly attached to the ε-amino groups of lysyl residues in arginine-rich histones (f2al and f3). Histone deacetylase attacked 14C-acetyllysyl residues in both f2al and f3 histones. In contrast, ε-N-14C-acetyl-histones prepared by the nonenzymatic acetylation with 14C-acetyl-CoA was deacetylated by this enzyme to a lesser extent. These results suggest that histones deacetylase has a high degree of specificity to distinguish specific acetyl-lysyl residues in histones.抄録全体を表示PDF形式でダウンロード (384K) -
Kentaro HORIUCHI, Daisaburo FUJIMOTO1972 年 72 巻 2 号 p. 433-438
発行日: 1972/08/25
公開日: 2008/11/18
ジャーナル フリーA histone acetylating enzyme was extracted from the cytoplasmic fraction of calf thymus and the sites in histone acetylated by the enzyme were studied. Acetylation of ε-amino group of lysyl residues of histone was catalyzed by the enzyme and the introduced acetyl groups were susceptible to histone deacetylase. The reaction of this enzyme appears to be like that occurring in the isolated nuclei. However, the enzyme of cytoplasm significantly acetylated only a particular histone species, f2al, while both f2al and f3 histones were acetylated in the isolated nuclei.抄録全体を表示PDF形式でダウンロード (362K) -
Yoshifumi TAKEDA, Kyoko MIYAZAKI, Kazuyoshi MATSUZAKI1972 年 72 巻 2 号 p. 439-446
発行日: 1972/08/25
公開日: 2008/11/18
ジャーナル フリーThe addition of 30S ribosomal subunits to purified 70S ribosomes stimulated polyphenylalanine synthesis in a cell free system of Escherichia coli, while the addition of 50S ribosomal subunits did not. The stimulation was not due to contamination of the 70S ribosomes with 50S ribosomal subunits or of the 30S ribosomal subunits with a protein factor (s) known to stimulate polyphenylalanine synthesis. It was also demonstrated that this stimulation was not due to the dissociation factor.抄録全体を表示PDF形式でダウンロード (557K) -
Yoshitada NOTSU, Seien OMURA, Akio YOSHIMOTO, Kenkichi TOMITA1972 年 72 巻 2 号 p. 447-457
発行日: 1972/08/25
公開日: 2008/11/18
ジャーナル フリーAn NAD-linked α-glycerophosphate dehydrogenase [EC 1. 1. 1. 8] activity was extracted from well washed mitochondria of rat liver by freezing-thawing the mitochondrial suspension or by exposing the particles to a phosphate buffer at pH 7.4. The dehydrogenase in mitochondrial extract was very similar to the one in the cytosol. Both dehydrogenases after the partial purification showed almost identical general properties with respect to the substrate specificity, pH optimum, apparent Km values for the substrates, molecular weight, and electrophoretic mobility.
However, in contrast to α-glycerophosphate dehydrogenase in the cytosol, the activity of this dehydrogenase extractable from mitochondria was influenced by the thyroid status of rats in a way similar to that of the respiratory chain-linked α-glycerophosphate oxidase system. By thyroidectomy, both its specific activity and tissue concentration were decreased to 50-60% of the control levels, and increased 1.5-2-fold in 3-4 days after a single injection of 3, 5, 3'-triiodo-L-thyronine to thyroid-ectomized rats. Furthermore, not only these changes were almost parallel to those of α-glycerophosphate oxidase activity, but also the tissue concentration of the dehydrogenase extractable from mitochondria during the thyroid hormone treatment was always higher than that of the oxidase.抄録全体を表示PDF形式でダウンロード (833K) -
Ikuo FUNAKOSHI, Ikuo YAMASHINA1972 年 72 巻 2 号 p. 459-467
発行日: 1972/08/25
公開日: 2008/11/18
ジャーナル フリーGlycopeptides were prepared by pronase digestion from membranous proteins of microsomes of an ascites hepatoma, AH 66, then fractionated to produce neutral and acidic glycopeptide fractions. The neutral fraction behaved nearly homogeneously on electrophoresis and contained only mannose and glucosamine as carbohydrate constituents, its composition being very similar to that of corresponding glycopeptides from rat liver microsomes. The acidic fraction was very heterogeneous, producing several peaks on column chromatography using DEAE-Sepahdex. Every peak contained neutral sugars (galactose, mannose, and fucose), glucosamine, and sialic acid, and the molar ratios of these constituents differed from one peak to another. Each peak was different from the corresponding glycopeptides from rat liver microsomes in its carbohydrate composition.抄録全体を表示PDF形式でダウンロード (693K) -
Masanobu TOKUSHIGE, Osamu HAYAISHI1972 年 72 巻 2 号 p. 469-477
発行日: 1972/08/25
公開日: 2008/11/18
ジャーナル フリー1. In order to elucidate the physiological role of ADP activation for the threonine deaminase [EC 4. 2. 1. 16] of Clostridium tetanomorphum, metabolism of threonine and its regulation by the nucleotide were investigated. αa-Ketobutyrate, a deamination product of L-threonine, was cleaved by a phosphoroclastic enzyme system to yield propionyl phosphate, CO2 and H2 in the presence of ferredoxin, CoA, and inorganic phosphate. Phosphate group in propionyl phosphate thus formed was transferred to ADP by a specific propionokinase to yield ATP and propionic acid.
2. Experiments with cell-free extracts fortified with added CoA, potassium phosphate and magnesium ions indicated that the rate of the formation of propionic acid from threonine was regulated by ADP concentration with a half saturation value of 0.14mM. In addition, the activation of threonine deaminase by ADP was competitively abolished by ATP with a Ki value of 0.69mM, which was almost 9 times higher than the Km for ADP under the experimental conditions employed.
3. A possible regulatory mechanism is proposed that the catabolism of threonine is linked to the generation of ATP and ADP accelerates the primary reaction, which appears to be the rate-limiting step in overall metabolism when the level of ATP decreases. ATP level is thus maintained by catabolic utilization of the substrate.抄録全体を表示PDF形式でダウンロード (689K) -
Nobuko SEND, Keiko ARIIZUMI, Sumi NAGASE, Kimiko ANNO1972 年 72 巻 2 号 p. 479-481
発行日: 1972/08/25
公開日: 2008/11/18
ジャーナル フリーPDF形式でダウンロード (785K) -
Koscak MARUYAMA, Sumiko KIMURA1972 年 72 巻 2 号 p. 483-486
発行日: 1972/08/25
公開日: 2008/11/18
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Hiroyuki KONDO, Makoto ISHIMOTO1972 年 72 巻 2 号 p. 487-489
発行日: 1972/08/25
公開日: 2008/11/18
ジャーナル フリーPDF形式でダウンロード (195K) -
Yasuhide YAMASAKI, Yasuo NATORI1972 年 72 巻 2 号 p. 491-493
発行日: 1972/08/25
公開日: 2008/11/18
ジャーナル フリーPDF形式でダウンロード (197K) -
Keizo WAKU, Yasuo NAKAZAWA1972 年 72 巻 2 号 p. 495-497
発行日: 1972/08/25
公開日: 2008/11/18
ジャーナル フリーPDF形式でダウンロード (189K)
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