巻号一覧
73 巻, 5 号
選択された号の論文の31件中1～31を表示しています
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V. Effect of Urea on the Structure of the Free Enzyme and Its Benzoate ComplexNobuhiko SUGIURA, Hirobumi OHAMA, Akira KOTAKI, Kunio YAGI1973 年 73 巻 5 号 p. 901-908
発行日: 1973/05/25
公開日: 2011/01/25
ジャーナル フリー1. Sedimentation and molecular sieve studies revealed that the dimeric form of D-amino acid oxidase [D-amino acid: O2 oxidoreductase (deaminating), EC 1. 4. 3. 3] or its benzoate complex dissociated quantitatively into the monomeric form upon addition of urea up to 2M.
2. Absorption and fluorescence data on the effect of 2 M urea indicated that the tertiary structure was slightly changed in the free enzyme, but not in its benzoate complex. Circular dichroism data supported the above results.
3. Slight changes in the tertiary structure of the free enzyme caused by 2 M urea were restored by complex formation with benzoate.
4. Data on the reduced mean residue rotation at 233 nm indicated that the secondary structure was not changed, both in the free enzyme and in its benzoate complex, upon addition of urea up to 4M.抄録全体を表示PDF形式でダウンロード (4950K) -
VI. Relation between the Quaternary Structure and the Catalytic ActivityKunio YAGI, Nobuhiko SUGIURA, Hirobumi OHAMA, Nobuko OHISHI1973 年 73 巻 5 号 p. 909-914
発行日: 1973/05/25
公開日: 2011/06/07
ジャーナル フリー1. The maximum velocity (Vmax/e0) of D-amino acid oxidase [D-amino acid: O2 oxidoreductase (deaminating), EC 1. 4. 3. 3] obtained by increasing the substrate concentration in the presence of 2M urea was found to be higher than that obtained in the absence of urea, though urea inhibited the enzymic reaction in competition with the substrate. The acceleration of the catalytic activity was ascribed to the dissociation of the dimer of the enzyme into its monomer.
2. Upon lowering the concentration of the enzyme, the value of Km was found to be increased, besides the acceleration of Vmax/e0 value, indicating that the Km. value is larger in the monomer than in the dimer.
3. The purple complex prepared in the presence of 2M urea gave the same absorp tion spectrum with that prepared in the absence of urea. However, they gave different values of s020, w; 3.5 S for the former and 6.9 S for the latter, indicating the occurrence of the purple intermediate of monomeric form during the catalytic reaction of the enzyme with neutral amino acids such as D-alanine in the presence of 2M urea.
4. The acceleration of the catalytic activity in the monomer was considered to occur after the formation of the purple intermediate, most probably during the liberation of the product, since the rate of formation of the purple intermediate was, larger in the dimer than in the monomer.抄録全体を表示PDF形式でダウンロード (3132K) -
VI. Prolonged Culture during Glucose StarvationShoji OKAMURA, Hiromi B. MARUYAMA, Tomomichi YANAGITA1973 年 73 巻 5 号 p. 915-922
発行日: 1973/05/25
公開日: 2011/01/25
ジャーナル フリーPhysiological changes in Escherichia coli starved of glucose were studied. After total exhaustion of the glucose in the medium, the cells showed a temporary loss of viability, the rate and extent of which differed in the three strains studied. The total ribonucleic acid (RNA) content also decreased in close correspondence with the degree of loss of viability. Ribosomal RNA synthesized in the exponential growth phase began to degrade during the linear phase before the decrease of viable cells with the occurrence of abnormal-sized particles. During the late stationary phase, RNA and protein were still synthesized, though at a lower rate, and a portion of the cells maintained their viability for more than 5 days.抄録全体を表示PDF形式でダウンロード (1476K) -
IV. Isolation of Two Inhibitors and Determination of Molecular Weights and Amino Acid CompositionsYoshio HOJIMA, Chiaki MORIWAKI, Hiroshi MORIYA1973 年 73 巻 5 号 p. 923-932
発行日: 1973/05/25
公開日: 2011/01/25
ジャーナル フリーTwo kallikrein [EC 3. 4. 4. 21] inhibitors from potatoes (PKI) were isolated from partially purified PKI preparations by two Ampholine isoelectric focusings. Their isoelectric points at 25°C were pH 5.6 and 6.4, and thus they were named PKI-56 and PKI-64. About 15 mg of each inhibitor was obtained in homogeneous form from 1 kg of potatoes after the whole purification procedure. Inhibitory activities of PKI- 56 and -64 against pure hog pancreatic kallikrein were 395 KIU/mg (dog vasodilative assay), 42.1 IU/mg (BAEE esterolytic assay), and 611 KIU/mg, 63.8 IU/mg, respectively.
Molecular weights of PKI-56 and -64 were determined to be 22, 000-25, 200 and 22, 000-27, 100, respectively, by the following methods: ultracentrifugation, Sephadex gel filtration and amino acid composition. The respective sedimentation coefficients (s20, w) were 2.20 and 2.27 S. It was suggested from the gel filtration results with Sephadex G-100 that 1 mole of both PKI's formed a complex with 1 mole of hog pancreatic kallikrein.
From the amino acid compositions and properties of both PKI's, differences between PKI and other proteinase inhibitors from the potato tuber were discussed, and it was concluded that both PKI's are newly isolated inhibitors from potatoes.抄録全体を表示PDF形式でダウンロード (4402K) -
V. Characterization of Two Isolated InhibitorsYoshio HOJIMA, Chiaki MORIWAKI, Hiroshi MORIYA1973 年 73 巻 5 号 p. 933-943
発行日: 1973/05/25
公開日: 2011/01/25
ジャーナル フリーSome properties of two isolated potato kallikrein inhibitors (PKI-56 and PKI-64) and their inhibitory activities towards kallikreins [EC 3. 4. 4. 21] and other proteinases have been studied. The following results were obtained.
1) Twenty minutes were necessary for both PKI's to form an equilibrated complex with hog pancreatic kallikrein (Hog Panc. K., homogeneous preparation) at 37°C and pH 8.0. The optimal pH of both PKI's was pH 8.0, and inhibition was found to be negligible at pH 4 for both PKI's.
2) Both PKI's were unstable against heat treatment at more than 60°C and also in the alkaline pH range. However, both were stable in the acidic pH range. 3) Dissociation constants (Ki) of Hog Panc. K.-PKI-56 were 4.0×10-6M (BAEE) and 4.6×10-6M (TAME), and those of Hog Panc. K.-PKI-64 were 2.2×10-6M (BAEE) and 3.0×10-6M (TAME) in the presence of BAEE or TAME substrates at 25°C and pH 8.0. In this case, the inhibition of both PKI's was competitive. In the absence of substrate, Ki values (calculated from [E][I]/[E-I]) of Hog Panc. K.-PKI-56, -PKI- 64, and -Trasylol were 1.2×10-6M, 7.4×10-7 M, and 1.4×10-8M, respectively. The final concentration of Hog Panc. K. in the preincubation mixture had a strong effect on the inhibitory activities of both PKI's. This may probably be based on the high dissociation constants of both PKI's.
4) Both PKI's showed stronger inhibitory activities to human plasma kallikreins and kallikrein-like enzymes from plasma than to glandular kallikreins. The specific inhibition of plasma enzymes was equal to or stronger than those of Trasylol and soy bean trypsin inhibitor. Both PKI's also inhibited trypsin [EC 3. 4. 4. 4], α-chymotrypsin [EC 3. 4. 4. 5], nagarse [EC 3. 4. 4. 16], and so on, though inhibition of these enzymes was weak. Both PKI's failed to inhibit thrombin [EC 3.4. 4.13] and papain [EC 3. 4. 4. 10].
5) Neither of the PKI's were digested by the above proteinases, even by pepsin [EC 3. 4. 4. 1] at pH 2.抄録全体を表示PDF形式でダウンロード (1745K) -
Effect of the Diphosphates of Aristeromycin and Cycloadenosine on the Polymerization of Adenosine Diphosphate by Polynucleotide PhosphorylaseMorio IKEHARA, Toshikazu FUKUI1973 年 73 巻 5 号 p. 945-950
発行日: 1973/05/25
公開日: 2011/01/25
ジャーナル フリーAristeromycin 5'-diphosphate (ArDP) and 8, 2'-anhydro-8-mercapto-9-β-D-arabinofuranosyladenine 5'-diphosphate (cycloadenosine DP or AsDP) were synthesized and tested for their properties in the polymerization catalyzed by E. coli polynucleotide phosphorylase [EC 2. 7. 7. 8].
AsDP was not either homopolymerized or copolymerized with ADP. However, it showed a stimulating effect in the polymerization of ADP to an extent of about 30%. Therefore, a site other than that responsible for polymerization would be involved in regulation of the reaction.
ArDP was a poor substrate for polynucleotide phosphorylase and the extent of its homopolymerization was only 0.9%. ArDP could be polymerized with ADP in the various ratios to give poly (A, Ar), which was analyzed by alkaline digestion to contain A and Ar residues randomly. UV and CD spectra of poly (A, Ar) were similar to those of poly A.抄録全体を表示PDF形式でダウンロード (901K) -
Yoki MORI, Nobukazu KAWAI, Jiro KOYAMA1973 年 73 巻 5 号 p. 951-958
発行日: 1973/05/25
公開日: 2011/01/25
ジャーナル フリーThe enzymatic measurement of binding of first component (C1) of guinea pig complement with antigen-antibody complexes is described. The reaction was based on the abilities of this component to bind with formalized sheep erythrocytes (FSE) sensitized with rabbit antiserum to sheep erythrocytes (SE) and to hydrolyze Nacetyl-L-tyrosine ethyl ester (ATEE). When sensitized FSE were incubated with guinea pig serum or partially purified C1 at 0°C and washed with an appropriate buffer, these materials showed esterolytic activity. This activity increased proportionally to the amount of rabbit antibody used for sensitization. When guinea pig serum was used as a source of C1 and the binding reaction was carried out at 37°C, no C1s activity developed, due to the coexistence of C1 inactivator. This blocked the esterolytic activity of C1s at 37°C immediately after the activation of C1s to C1s. As the binding of C1 with sensitized FSE proceeded rapidly and also quantitatively at 0°C, this reaction could be used for the enzymatic determination of C1 activity, independently of whether preparations of C1 to be tested contained C1 inactivator or not.抄録全体を表示PDF形式でダウンロード (1495K) -
II. Limnodrilus Hemoglobin and Its DerivativesYoshiie OKADA, Kazuo OKUNUKI1973 年 73 巻 5 号 p. 959-963
発行日: 1973/05/25
公開日: 2011/01/25
ジャーナル フリーThe CD spectra of Limnodrilus oxy-, deoxy-, carbon monoxyferro-, ferri-, and cyanoferrihemoglobin are reported. The positions and magnitudes of the circular dichroic bands varied with ligand substitution and with the oxidation state of the heme iron. The Soret CD spectra of Limnodrilus hemoglobin and its derivatives support the rules so far suggested. The amplitudes of the CD bands at about 260mμ varied with the spin state of the heme iron: the optical activity of compounds with low spin moments was considerably greater than that of compounds with high spin.抄録全体を表示PDF形式でダウンロード (707K) -
III. Cytochrome b5 from Rabbit Liver Microsomes, and Cytochrome b-557.5 from Rhodospirillum rubrumYoshiie OKADA, Kazuo OKUNUKI1973 年 73 巻 5 号 p. 965-969
発行日: 1973/05/25
公開日: 2011/01/25
ジャーナル フリーThe similarity of the Soret CD spectra among larval cytochromes b-555 and b-563 from the housefly, rabbit liver cytochrome b5s' solubilized by trypsin and by detergent, and R. rubrum cytochrome b-557.5 in either oxidation state suggests a quite similar steric environment around the heme group for these five b-type cytochromes and indicates that there is no conformational change around the heme group in these cytochrome molecules on release from membranes by proteolytic digestion or by detergent treatment.
Features of both the oxidized and reduced Soret CD spectra of rabbit liver cytochrome b5s' solubilized by trypsin and by detergent, and of R. rubrum cytochrome b-557.5 agree well with the rules suggested in our previous papers.抄録全体を表示PDF形式でダウンロード (1022K) -
Misako HIRAMATSU, Nobuo OKABE, Ken-ichi TOMITA1973 年 73 巻 5 号 p. 971-978
発行日: 1973/05/25
公開日: 2011/01/25
ジャーナル フリーHen egg-white lysozyme [EC 3. 2. 1. 17] was labelled with fluorescein-isothiocyanate (FITC). Three samples of FTC-lysozyme (S-A, S-B, and S-C) were prepared and the average amount of bound dye was 4 moles per mole of protein for S-A, 2 for S-B, and 1.5 for S-C. The enzymatic activity, circular dichromism (CD) and fluorescence characteristics of these conjugates were studied. The enzymatic activity of these labelled lysozymes on glycol chitin was almost the same as that of native lysozyme. No measurable change occurred in the 210-250 nm region of the CD spectra, whereas the CD spectra in the aromatic absorption region at 250-300 nm and the tryptophyl fluorescence spectra of FTC-lysozyme changed considerably with the degree of labelling, and it was suggested that at a high degree of labelling there might be some interaction between FTC groups and aromatic amino acid residues, probably tryptophyl residues, of the lysozyme molecule.抄録全体を表示PDF形式でダウンロード (1185K) -
III. Comparison of Lipid and Protein Components of Na, K-ATPase Preparations at Various Purification Steps from Pig BrainKoichi KAWAI, Makoto NAKAO, Toshiko NAKAO, Michiya FUJITA1973 年 73 巻 5 号 p. 979-991
発行日: 1973/05/25
公開日: 2011/01/25
ジャーナル フリー1. Lipid and protein composition of various Na, K-ATPase [EC 3. 6. 1. 3] preparations in the course of purification including highly purified preparations was estimated. The total amounts of neutral lipid, phospholipid, cerebroside, and ganglioside as well as the composition of neutral lipids and phospholipids were determined using mainly thin-layer-chromatography. SDS-polyacrylamide gel electrophoresis was carried out for the determination of polypeptide components. These analyses were designed to see the lipoprotein nature of this enzyme.
2. Variety of the lipid composition at various steps of purication was not so great as that of polypeptide components observed in a SDS-disc gel electrophoresis. However, it is evident that the relative phosphatidyl serine content increased with purification.
3. Pools of the three different Na, K-ATPase preparations which were obtained with AE-cellulose column chromatography and showed specific activities of 1, 000-1, 700 μ moles of inorganic phosphate released, hr-1, mg protein-1 had very large amounts of lipids compared with crude enzyme preparations, and their phospholipid compositions were also different from one another.抄録全体を表示PDF形式でダウンロード (9438K) -
Naoki YAMANAKA, Toshio IMANARI, Zenzo TAMURA, Kunio YAGI1973 年 73 巻 5 号 p. 993-998
発行日: 1973/05/25
公開日: 2011/01/25
ジャーナル フリー1. Chinoform (5-chloro-7-iodo-8-quinolinol) uncoupled the oxidative phosphorylation of rat liver mitochondria in the presence of Mg ions.
2. Release of the controlled respiration was induced by chinoform both in the presence and absence of inorganic phosphate, and was insensitive to oligomycin. ATPase activity of intact mitochondria was induced by chinoform in the presence of Mg ions, and was inhibited by oligomycin. These data indicate that chinoform affects the “non-phosphorylated high-energy intermediate.”
3. Prior addition of Mg ions was essential for the uncoupling action of chinoform. Chinoform-Mg chelate uncoupled oxidative phosphorylation in the absence of Mg ions. Mg ions could be replaced by other cations such as Fe ions.
4. Chinoform glucuronide (5-chloro-7-iodo-8-quinolyl-β-D-glucuronic acid) had no uncoupling action.抄録全体を表示PDF形式でダウンロード (1002K) -
Toshihiko HAYASHI, Yutaka NAGAI1973 年 73 巻 5 号 p. 999-1006
発行日: 1973/05/25
公開日: 2011/01/25
ジャーナル フリーDenaturation temperature of pepsin-treated collagen from calf skin was measured viscometrically in neutral pH solution by adding glucose which completely depresses collagen fibril formation without denaturing collagen molecules.
The stability of collagen molecules in solution thus obtained was greater at neutral pH than at either acidic or basic pH. The capability of renaturation from denatured state was also highest at neutral pH. The renaturation of denatured collagen molecules seemed even more sensitive to pH of the solution than the denaturation of native ones.抄録全体を表示PDF形式でダウンロード (1476K) -
Shigeto ABE, Masayuki SHINMEI, Yutaka NAGAI1973 年 73 巻 5 号 p. 1007-1011
発行日: 1973/05/25
公開日: 2011/01/25
ジャーナル フリー1. The contents of collagenase and α-globulins in synovial fluids from patients with various joint diseases including rheumatoid arthritis have been investigated.
2. The presence of large amount of collagenase in a latent form was demonstrated in the fluids from patients with rheumatoid arthritis and osteoarthritis. The collagenase could be activated by the treatment with 3M NaSCN.
3. Regardless of types of joint diseases, synovial fluids contained more a1-antitrypsin than α2-macroglobulin.
4. Rheumatoid synovial fluids contained more α1-antitrypsin and α2-macroglobulin than the non-rheumatoid.
5. Close relation between the amount of collagenase in a latent form and the degree of articular destruction in various joint diseases was discussed.抄録全体を表示PDF形式でダウンロード (855K) -
Tadashi YOSHIDA, Goro KIKUCHI1973 年 73 巻 5 号 p. 1013-1022
発行日: 1973/05/25
公開日: 2011/01/25
ジャーナル フリーThe metabolism of serine and glycine in the liver, kidney, spleen, testis, brain, spinal cord, heart, lung, skeletal muscle, and small intestine of rats and cocks was studied with whole tissue homogenates, soluble tissue fractions, and mitochondria. The soluble tissue fractions of all organs tested contained serine hydroxymethyltransferase [EC 2. 1. 2. 1] and methylene-THF dehydrogenase [EC 1. 5. 1. 5]. On the other hand, the distribution of L-serine dehydratase [EC 4. 2. 1. 13] was very limited; only rat liver and kidney contained significant activity and the activity in the latter being very low. Methylene-THF, formed from the β-carbon of serine, can be further oxidized to CO2 either by soluble fractions or mitochondria of most rat organs. This may be due to the sequential actions of methylene-THF dehydrogenase, cyclohydrolase [EC 3. 5.4. 9], and 10-formyl-THF; NADP+ oxidoreductase. In contrast, preparations from various organs of cocks caused no appreciable catalysis of the oxidation of the β-carbon of serine or formaldehyde to CO2. This is probably because the: activity of 10-formyl-THF; NADP+ oxidoreductase is extremely low in these organs.
It was also found that the glycine cleavage system is important in glycine degradation in the liver, kidney, brain, and testis of both rats and cocks. All other organs from these animals except heart caused scarcely any catabolism of glycine to CO2. In heart there was considerable glycine catabolism, which did not appear to occur by either the glycine cleavage or the glyoxylate pathway. It was concluded that serine catabolism in rats and cocks can be accounted for mainly by the cleavage of serine to form methylene-THF and glycine, followed by the cleavage of glycine to methylene-THF, CO2, and ammonia, and that this is also the major pathway of glycine degradation in both rats and cocks.抄録全体を表示PDF形式でダウンロード (1719K) -
III. General Properties and Specificity of EndonucleaseIkuo SUHARA1973 年 73 巻 5 号 p. 1023-1032
発行日: 1973/05/25
公開日: 2011/01/25
ジャーナル フリーThe general properties and substrate specificity of the endonuclease from Acrocylindrium sp. were examined.
1. The optimum pH of the endonuclease is 8.0.
2. The endonuclease requires divalent cations such as Mn2+, CO2+, Mg2+, Pb2+, Ca2+, etc. for its activity.
3. The endonuclease is relatively stable towards heat treatment (100°C, 5 min, at pH 7.5).
4. The order of relative rate of hydrolysis of substrates is native DNA>heat-denatured DNA>RNA>poly C>poly U>poly A>poly I.
5. Oligonucleotides thus produced are terminated by 5'-phosphoryl groups and showed an average chain length of 4.4.
6. The enzyme hydrolyzes double-stranded polyribonucleotides such as poly I: poly C or poly A: poly U more rapidly than single-stranded polyribonucleotides.
7. The usefulness of this enzyme as a reagent for the structural analysis of nucleic acids, together with the exonuclease from Acrocylindrium sp., is discussed.抄録全体を表示PDF形式でダウンロード (1548K) -
IV. Intracellular Localization of NADH2-glyoxylate Reductase in Rat LiverShigeru SUZUKI, Tetsuya SUGA, Shinkichi NIINOBE1973 年 73 巻 5 号 p. 1033-1038
発行日: 1973/05/25
公開日: 2011/01/25
ジャーナル フリーThe intracellular localization of NADH2-glyoxylate reductase [EC 1. 1. 1.26] in rat liver was studied.
When liver was homogenized and subjected to differential centrifugation in 0.25 M sucrose, the specific activity was highest in the microsomal fraction and there was also a considerable activity in the supernatant fraction. However, when these procedures were carried out in 0.15 M KCl, the supernatant fraction contained most activity.
NADH2-glyoxylate reductase associated with the crude particle fraction (3, 300×g, 10 min-156, 500×g, 60 min) prepared in 0.25 M sucrose was easily solubilized by wsahing with CsCl or KCl and it was also readily released from the particles at KCl concentrations below the physiological concentration.
From these resuls, it was concluded that the enzyme is in a soluble form in the cytoplasm, but not in the peroxisomes, and that ionogenic interaction of the enzyme with the microsomal membranes takes place during homogenization of the tissues in 0.25M sucrose.抄録全体を表示PDF形式でダウンロード (980K) -
Teruo IWASAKI, Toshifumi KIYOHARA, Mitsuyoshi YOSHIKAWA1973 年 73 巻 5 号 p. 1039-1048
発行日: 1973/05/25
公開日: 2011/01/25
ジャーナル フリーLimited hydrolysis of potato proteinase inhibitor II-a with a catalytic quantity of TPCK-treated bovine trypsin [EC 3. 4. 4. 4] at pH 3 results in the selective cleavage of a single Lys-Ser bond of the inhibitor. Fragmentation of the enzymatically modified inhibitor by reduction, S-carboxymethylation, and gel filtration reveal that the Lys-Ser bond is that between residues 63 and 64 of the inhibitor. This peptide bond is also selectively split by a catalytic quantity of TLCK-treated bovine chymotrypsin [EC 3.4. 4.5] at the same pH. The modified inhibitor retains full activities against trypsin, chymotrypsin, and a bacterial proteinase, Nagarse. However, the elimination of the newly formed carboxyl-terminal lysine from the modified inhibitor by carboxypeptidase B [EC 3.4. 2.2] digestion is accompanied by virtually complete loss of activity against trypsin and also by considerable reduction of the activities against chymotrypsin and Nagarse. It was therefore concluded that the Lys-Ser bond of residues 63 and 64 in inhibitor II-a is not only the reactive site for trypsin but is also the main reactive site for chymotrypsin and Nagarse of the inhibitor.抄録全体を表示PDF形式でダウンロード (1627K) -
I. Combination of Alkyl Isonitriles with Cytochrome αTakashi YAMAMOTO, Yutaka ORII1973 年 73 巻 5 号 p. 1049-1059
発行日: 1973/05/25
公開日: 2011/01/25
ジャーナル フリー1. In the presence of isonitrile at a concentration lower than that of ferroheme α, a 1: 1 heme a-isonitrile complex was formed, whereas above that concentration a 1: 2 complex was formed.
2. Ferrocytochrome α(cytochrome oxidase)[EC 1.9. 3. 1] combined with alkyl isonitriles and its combining power for the isonitriles depended on the size of the alkyl groups. The dissociation constants of cytochrome α-isonitrile complexes were calculated to be 2×10-4M and 2×10-2 M for ethyl and tertiary-butyl isonitriles, respectively. The results suggested that the heme α prosthetic group was situated in a crevice of the cytochrome α molecule.抄録全体を表示PDF形式でダウンロード (1762K) -
VII. Properties of Homoserine O-TransacetylaseRyuichi MIYAJIMA, Isamu SHIIO1973 年 73 巻 5 号 p. 1061-1068
発行日: 1973/05/25
公開日: 2011/01/25
ジャーナル フリーHomoserine O-transacetylase was purified about 10-fold from sonic extracts of a methionine-less mutant, strain M-116, derived from Brevibacterium flavum No.2247 (wild type). This purification resulted in about an 80-fold increase in specific activity over that of the wild strain. Acetyl-CoA, but not succinyl-CoA, was effective as an acyl donor. The reaction mechanism is suggested to be “ping pong” type. Km values for homoserine and acetyl-CoA were 2.8 and 0.05 mM, respectively. The enzyme activity was not inhibited by methionine and/or S-adenosylmethionine. Homocysteine also gave no inhibitory effect. O-Acetylhomoserine, one of the reaction products, inhibited the enzyme activity in a mixed manner with respect to both substrates. The formation of homoserine O-transacetylase in B. flavum was strongly and almost completely repressed by methionine. The repression of homoserine dehydrogenase [EC 1. 1. 1. 3] by methionine might not be coordinate with that of homoserine O-transacetylase. Based on these results, the regulation of methionine biosynthesis in this bacterium is discussed.抄録全体を表示PDF形式でダウンロード (1570K) -
Parahydrogen-Orthohydrogen Conversion and Hydrogen-Deuterium Exchange ReactionsTatsuhiko YAGI, Motoyuki TSUDA, Hiroo INOKUCHI1973 年 73 巻 5 号 p. 1069-1081
発行日: 1973/05/25
公開日: 2011/01/25
ジャーナル フリーThe kinetics of paraH2-orthoH2 conversion and the H-D exchange reactions catalyzed by highly purified desulfovibrio hydrogenase [H2: ferricytochrome c3 oxidoreductase] were studied.
These reactions were catalyzed by the enzyme in the absence of cytochrome c3, but were, in general, stimulated by the cytochrome. In the reaction system with paraH2 over D2O, the conversion of paraH2 to normal H2, as well as the isotope exchange reactions, were catalyzed by the enzyme, in contrast to earlier observations made with rather crude hydrogenase preparations from other species of bacteria. This reaction was not stimulated, or even inhibited, by cytochrome c3.
Kinetic analyses of the rates of these reactions revealed that the two hydrogen atoms of the enzyme-bound hydrogen molecule have different exchange rates with hydrogen ions of the medium.
All the kinetic constants for individual steps of the conversion and exchange reactions catalyzed by aqueous hydrogenase were calculated. A possible mechanism for the binding of a hydrogen molecule to the enzyme was proposed.抄録全体を表示PDF形式でダウンロード (1861K) -
VI. Biosynthesis of Catalase by Free and Membrane-bound PolysomesTerufumi SAKAMOTO, Tokuhiko HIGASHI1973 年 73 巻 5 号 p. 1083-1088
発行日: 1973/05/25
公開日: 2011/01/25
ジャーナル フリーIt was found that both free and membrane-bound polysomes synthesize catalase [EC 1. 11. 1. 6] in rat liver. The polysomes synthesizing catalase and the nascent catalase peptides involved in these two types of polysomes were labeled in vivo at almost the same rate on injection of radioactive leucine. Similar results were obtained on in-. corporation of 14C-leucine using cell-free systems derived from free and bound polysomes.抄録全体を表示PDF形式でダウンロード (943K) -
Michiaki KOHNO, Ikuo YAMASHINA1973 年 73 巻 5 号 p. 1089-1094
発行日: 1973/05/25
公開日: 2011/01/25
ジャーナル フリーRat serum proteins were labelled by injecting L-aspartic acid-2, 3-3H and L-asparagine-2, 3-3H to see whether the amino acid linked to carbohydrate through the aspartylglycosylamine linkage in serum glycoproteins is derived from aspartic acid or from asparagine during biosynthesis. Labelled serum proteins were digested with pronase to produce glycopeptides (glycosylated asparagine) and peptides plus amino acids. Glycopeptides from serum proteins obtained from either 3H-aspartic acid- or 3H-asparagine-administered rats were radioactive. In view of the possible metabolic interconversion of aspartic acid and asparagine, the specific activities of glycosylated asparagine were compared to those of aspartic acid and asparagine, constituting peptides plus amino acids, as represented by the activities of free aspartic acid and asparagine. For this, aspartic acid was isolated by paper electrophoresis. Asparagine was isolated as aspartic acid in a similar manner after the removal of aspartic acid by resin treatment followed by asparaginase digestion. The specific activities of glycosylated asparagine nearly equalled those of asparagine, but differed markedly from those of aspartic acid, which led us to conclude that glycosylated asparagine is derived from asparagine.抄録全体を表示PDF形式でダウンロード (1248K) -
III. Molecular Characteristics of EF-Tu-Guanosine Diphosphate, EF-Ts, and EF-Tu-Ts ComplexKen-ichi ARAI, Masao KAWAKITA, Yoshito KAZIRO, Toshihiko KONDO, Nobuo ...1973 年 73 巻 5 号 p. 1095-1105
発行日: 1973/05/25
公開日: 2011/01/25
ジャーナル フリーIn the preceding paper we described a procedure for the large-scale purification of the polypeptide elongation factors Tu-GDP, Ts, and Tu-Ts from E. coli. These three factors were purified to a homogeneous state as judged by several criteria, and Tu-GDP and Tu-Ts were crystallized. Here we report some of the molecular and physicochemical characteristics of these factors, including molecular weight, amino acid composition, and absorption spectrum.
The molecular weights of Tu-GDP, Ts, and native Tu-Ts, as determined by the Yphantis high-speed sedimentation equilibrium method, were 47, 000, 34, 000, and 66, 000, respectively. Tu-Ts complex reconstituted from Tu-GDP and Ts had a molecular weight of 68, 000. The molecular weights of Tu and Ts were also determined by SDS polyacrylamide gel electrophoresis, and values of 47, 000 and 36, 000 were estimated for Tu-GDP and Ts, respectively. On the other hand, the Sephadex gel filtration of Tu-GDP, Ts, and Tu-Ts gave molecular weights of 48, 000, 48, 000, and 92, 000, respectively. As described previously, the binding of [3H] GDP to Tu was one mole of GDP per 44, 000 to 48, 000 g of protein. By a spectrophotometric procedure, the amount of GDP bound to Tu-GDP was estimated as one mole of GDP per 49, 000 g of protein. It was concluded that both Tu and Ts contain no subunit structure, and that Tu-Ts was a complex consisting of one mole each of Tu and Ts.
The amino acid compositions of Tu-GDP, Ts, and Tu-Ts were determined. Tu and Ts contained 3 and 2 residues of cysteine per mole of protein, respectively. Ts contained no tryptophan, and very little tyrosine. The amino acid composition of Tu-Ts was in good agreement with the values calculated from those of Tu and Ts, assuming the molar ratio of Tu and Ts in Tu-Ts complex as one. The absorption spectrum of Tu-GDP indicated the presence of bound GDP, while that of Ts showed no typical absorption peak at 280 mμ, as expected from its amino acid composition.抄録全体を表示PDF形式でダウンロード (1652K) -
Tsunehiro MUKAI, Ken-ichi MATSUBARA, Yasuyuki TAKAGI1973 年 73 巻 5 号 p. 1107-1109
発行日: 1973/05/25
公開日: 2011/01/25
ジャーナル フリーPDF形式でダウンロード (522K) -
Keiichi YAMAMOTO, Koscak MARUYAMA1973 年 73 巻 5 号 p. 1111-1114
発行日: 1973/05/25
公開日: 2011/01/25
ジャーナル フリーPDF形式でダウンロード (4922K) -
Hiroko SATOH, Yukio KUROIWA, Akira HAMADA1973 年 73 巻 5 号 p. 1115-1118
発行日: 1973/05/25
公開日: 2011/01/25
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Ryoko TSUKUI, Setsuro EBASHI1973 年 73 巻 5 号 p. 1119-1121
発行日: 1973/05/25
公開日: 2011/01/25
ジャーナル フリーPDF形式でダウンロード (1973K) -
Hirobumi OHAMA, Nobuhiko SUGIURA, Kunio YAGI1973 年 73 巻 5 号 p. 1123-1125
発行日: 1973/05/25
公開日: 2011/01/25
ジャーナル フリーPDF形式でダウンロード (375K) -
Jun-ichi AZUMA, Masanobu JANADO, Konoshin ONODERA1973 年 73 巻 5 号 p. 1127-1130
発行日: 1973/05/25
公開日: 2011/01/25
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Tadahiko ANDO, Shukuko IKAWA, Eiji HAYASE1973 年 73 巻 5 号 p. 1131-1134
発行日: 1973/05/25
公開日: 2011/01/25
ジャーナル フリーPDF形式でダウンロード (2261K)
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