巻号一覧
77 巻, 6 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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Toyoki KATO, Yuji TONOMURA1975 年 77 巻 6 号 p. 1127-1134
発行日: 1975/06/25
公開日: 2008/11/18
ジャーナル フリーA contractile protein closely resembling natural actomyosin (myosin B) of rabbit skeletal muscle was extracted from plasmodia of the slime mold, Physaruln poly-cephalum, by protecting the SH-groups with 8-mercaptoethanol or dithiothreitol. Superprecipitation of the protein induced by Mg2+-ATP at low ionic strength was observed only in the presence of very low concentrations of free Call ions, and the Mg2+-ATPase [EC 3. 6. 1. 3] reaction was activated 2- to 6-fold by 1 μM of free Ca2+ ions.
Crude myosin and actin fractions were separated by centrifuging plasmodium myosin B in the presence of Mg2+-PP1 at high ionic strength. The crude myosin showed both EDTA- and Ca2+-activated ATPase activities. The Mg2+-ATPase activ-ity of crude myosin from plasmodia was markedly activated by the addition of pure F-actin from rabbit skeletal muscle, Addition of the F-actin-regulatory protein com-plex prepared from rabbit skeletal muscle as well as the actin fraction of plasmodium caused the same degree of activation as the addition of pure F-actin only in the presence of very low concentrations of Ca2+ ions, and caused only slight activation in the absence of free Ca2+ ions.抄録全体を表示PDF形式でダウンロード (1994K) -
Akio INOUE, Yuji TONOMURA, Shizuo WATANABE1975 年 77 巻 6 号 p. 1135-1145
発行日: 1975/06/25
公開日: 2008/11/18
ジャーナル フリーInteractions of ITP with rabbit skeletal heavy-meromyosin (HMM) and with acto-heavy-meromyosin (acto-HMM) were studied by using transient as well as steady-state kinetics. (1) The results obtained from the studies of HMM-ITPase [EC 3. 6. 1. 3] in the steady state and of changes in the UV-absorption spectrum of HMM can be summarized by the following proposed reaction scheme (1):
M+ITPM_??_•ITP_??_MIDPP_??_M+IDP+Pi (1)
The kinetic parameters in the scheme were estimated to be as follows: K1=40 μM, k2=62.5 sec-1, k-2_??_k2, and k4=0.6 sec-1. (2) The steady-state activity of acto-HMM-ITPase was found to consist of two different activities, and the following reaction scheme (2) is proposed to accomodate the findings:
AM+ITP_??_A+MIDPP_??_(2a)
M+ITP_??_AMPIDPP_??_(2b).
The two activities are thus characterized by different sets of kinetic parameters: we found Km=0.9 μM and Vmax=0.7 sec-1 in one set, whereas K'm=160 μM and V'max=20-30 sec-1 in the other. (3) The dissociation of acto-HMM, and reassociation of F-actin and HMM were studied by using the light-scattering technique. The results obtained indicate that ITP, when added to acto-HMM, induces a special state in HMM, and that the HMM in this special state, denoted by M (R), is free from IDP and Pi, and is nonetheless incapable of binding to F-actin. It is therefore proposed that the following reaction step should be added to the scheme (2a):
MIDPP_??_M(R)+IDP+P1 M+IDP+P1
The value of k5 for the reaction in which M (R) returns to a normal state of HMM (denoted as M) was estimated to be 0.08 sec-1.抄録全体を表示PDF形式でダウンロード (685K) -
Competition for Cellular Reducing PowerHaruo WATANABE, Naotoshi MIMURA, Atsushi TAKIMOTO, Takao NAKAMURA1975 年 77 巻 6 号 p. 1147-1155
発行日: 1975/06/25
公開日: 2008/11/18
ジャーナル フリーChanges in the in vivo luminescence, respiratory activities, contents of cytochromes, extractable luciferase and NAD(P)H-FMN reductase during growth of the wild (bright) strain of Photobacterium phosphoreum and its dim mutant were determined. The intensity of the in vivo luminescence per cell increased 10 times in the wild strain and 750 times in the dim strain during logarithmic growth, while the contents of luciferase and NAD(P)H-FMN reductase remained almost constant. It is suggested that a characteristic change in the mode of competition of the luminescence reaction system with another electron transfer chain involving cytochromes for NAD(P)H takes place during the growth of this bacterium.抄録全体を表示PDF形式でダウンロード (652K) -
Improved Model for the Elongation Process by Protein SubunitsYoshimi OKADA, Takeshi OHNO, Yoshiaki NONOMURA1975 年 77 巻 6 号 p. 1157-1163
発行日: 1975/06/25
公開日: 2008/11/18
ジャーナル フリーThe in vitro assembly reaction of tobacco mosaic virus (TMV), especially the elon-gation process of partially reconstituted RNA (PRR) by protein subunits, was observed by electron microscopy. After addition of TMV-protein subunits, the PRR appeared as rods with a clump at one end, believed to be a complex between added protein subunits and the RNA tail protruding from PRR. The subunits entrapped on the RNA tails in the forms of clumps were progressively incorporated into the growing rods on incubation, ending with the formation of completely reconstituted rods. The clumps were also observed after addition of cucumber green mottle mosaic virus (CGMMV) protein subunits to rods partially reconstituted from RNA and TMV-protein. In this case, the protein subunits, seen as clumps, did not become incorporated to form elongating rods.
An improved model for the elongation of TMV rods is proposed. The elongation process is composed of two steps, with the first step being the interaction of protein subunits with the RNA tail protruding from the growing rod. Any protein having a specific binding site for TMV-RNA, not limited to TMV-protein, will react in the first step. The second step is the incorporation of the protein on the RNA tail into a rod-shaped structure, with consequent elongation of the growing rod. It appears that only protein homologous with that in the partially reconstituted rods can partake in the second step抄録全体を表示PDF形式でダウンロード (2653K) -
Fujio EGAMI1975 年 77 巻 6 号 p. 1165-1169
発行日: 1975/06/25
公開日: 2008/11/18
ジャーナル フリーIn this paper we speculate on the origin and early evolution of transition element enzymes. Iron, molybdenum, and zinc, the most abundant transition elements in seawater, presumably complexed with compounds accumulated in the primeval sea in the course of chemical evolution forming compounds which subsequently evolved to form proenzymes or early enzymes with low activity and broad specificity.
Iron complexes may be regarded as precursors of electron transfer enzymes, molybdenum complexes as precursors of enzymes involved in the metabolism of small molecules, and zinc complexes as precursors of hydrolytic and transferring enzymes, including enzymes participating in the metabolism of macromolecules and information transfer.
The different iron, molybdenum, and zinc enzymes found in bacteria including Clostridium may then have arisen through specialization by increases in the enzyme specificity of these proenzymes. Copper would have been incorporated as an enzyme constituent after the elevation of environmental redox potential, probably due to the accumulation of atmospheric oxygen.抄録全体を表示PDF形式でダウンロード (348K) -
Showbu SATO, Tsuneko UCHIDA1975 年 77 巻 6 号 p. 1171-1176
発行日: 1975/06/25
公開日: 2008/11/18
ジャーナル フリーRNase U2 was partially hydrolyzed with chymotrypsin [EC 3. 4. 21. 1] and sulfuric acid, and in each case the resulting peptides were separated by gel filtration, ion exchange column chromatography and paper electrophoresis. From the results of amino acid analysis of cystine-containing peptides and their oxidized components, the three disulfide bridges were located between the cystine residues at positions 1 and 53, 9 and 112, and 54 and 95.抄録全体を表示PDF形式でダウンロード (334K) -
Akira HACHIMORI, Atsushi TAKEDA, Minoru KAIBUCHI, Nobuyasu OHKAWARA, T ...1975 年 77 巻 6 号 p. 1177-1183
発行日: 1975/06/25
公開日: 2008/11/18
ジャーナル フリーInorganic pyrophosphatase [EC 3. 6. 1. l] was purified from Bacillus stearothermophilus to a homogeneous state both ultracentrifugally and electrophoretically. Ultracentrif-ugal analysis revealed that the molecular weight of the enzyme is 122, 000 and the sedimentation coefficient (S0.34%20 W) is 5.2S. The enzyme molecule in 0.1% sodium dodecylsulfate solution containing 1 mM 2-mercaptoethanol had an estimated molec-ular weight of 70, 000 on the basis of SDS-polyacrylamide gel electrophoresis results, which indicates that the enzyme may consist of two subunits. Divalent cations such as Mg2+, Mn2+, and Co2+ are required for the enzymatic activity. Pyrophosphate is the only substrate for the enzyme. ATP and p-chloromercuribenzoate inhibit the enzyme reaction markedly.抄録全体を表示PDF形式でダウンロード (1177K) -
I. Separation and Properties of Low-density LipoproteinsJun-ichi AZUMA, Naoki KASHIMURA, Tohru KOMANO1975 年 77 巻 6 号 p. 1185-1192
発行日: 1975/06/25
公開日: 2008/11/18
ジャーナル フリーThe low-density lipoproteins in pig serum were separated into two subclasses (LDL1, and LDL2) by 2 to 7% pore size gradient gel electrophoresis. Preparative gel elec-trophoresis in 2 to 4%o gradient gel made it possible to isolate these components as distinct entities. After delipidation by chromatography on Sepharose 4B in the presence of SDS, both apo-LDL1, and apo-LDL2 were found to have a molecular weight of 2.6×105. However, when these apoproteins were incubated in 10% sodium dodecyl sulfate, fragmentation occurred and the minimum fragment molecular weight was estimated to be 2.4×104. No essential difference was found in the amino acid com-positions or fragmentation patterns of the apoproteins. However, the amounts of carbohydrates in the two apoproteins were different (7.09% in apo-LDL1, and 5.08% in apo-LDL2). The carbohydrate composition was 0.8% sialic acid, 2.38% N-acetyl-glucosamine, and 4.01% neutral sugars in apo-LDL1, and 0.5, 1.75, and 2.83% in apo-LDL2, respectively. In both apoproteins, mannose, galactose, and fucose were present in almost the same molar ratio of 4-5:2-3:1.抄録全体を表示PDF形式でダウンロード (2506K) -
Takaaki KOBAYASHI1975 年 77 巻 6 号 p. 1193-1197
発行日: 1975/06/25
公開日: 2008/11/18
ジャーナル フリー1. Tubulin purified from porcine brain in the presence of GTP contained 0.16 mole of GDP and 0.73 mole of GTP per 60, 000 g of protein.
2. Microtubules reconstituted from the purified tubulin contained 0.43 mole of GDP and 0.41 mole of GTP per 60, 000g of protein. Guanine nucleotide bound to the exchangeable site of tubulin was converted to GDP during microtubule assembly, while GTP at the non-exchangeable site remained intact.
3. Guanine nucleotide which had been bound to the exchangeable site of tubulin before microtubule assembly was also exchangeable during disassembly.抄録全体を表示PDF形式でダウンロード (337K) -
V. Effect of Ethyl p-Chlorophenoxyisobutyrate on the Centrifugal Behavior of Rat Liver PeroxisomesHidenori HAYASHI, Tetsuya SUGA, Shinkichi NIINOBE1975 年 77 巻 6 号 p. 1199-1204
発行日: 1975/06/25
公開日: 2008/11/18
ジャーナル フリーAfter Wistar male rats had been fed on a diet containing 0.25% of ethyl p-chloro-phenoxyisobutyrate (CPIB) for 28 days, changes in the enzyme activities and centrif-ugal behavior of rat liver peroxisomes were investigated. (1) Compared with control rats fed on the basal diet, the catalase [EC 1. 11. 1. 6] activity of rat livers after the administration of CPIB increased about 2.5-fold, while urate oxidase [EC 1. 7. 3. 3] activity did not change significantly. Though D-amino acid oxidase [EC 1. 4. 3. 3] activity markedly decresed to approximately one-sixth of the control, the activity of L-α-hydroxy acid oxidase [EC 1. 1. 3. 15], a flavin enzyme like D-amino acid oxidase, was not affected significantly after the administration of CPIB. (2) When the hepatic cells of CPIB-treated rats were fractionated by differential centrifugation, most of the increase of catalase activity appeared in the supernatant fraction. A decrease in the hepatic D-amino acid oxidase activity of CPIB-treated rats was observed in all the fractions. As for the subcellular distribution of the particle-bound enzymes, the specific activities of both catalase and urate oxidase of CPIB-treated rat livers were higher in the light mitochondrial fraction than in other fractions. (3) Sedimentation patterns in a sucrose density gradient did not show any difference between normal peroxisomes and CPIB-treated ones. (4) In the case of CPIB-treated rats, studies of their sedimentation patterns by Ficoll density gradient centrifugation showed two main particulate peaks containing both catalase and urate oxidase, although only a single peak was observed in the case of control rats.抄録全体を表示PDF形式でダウンロード (431K) -
Kazuko OBA, Ikuzo URITANI1975 年 77 巻 6 号 p. 1205-1213
発行日: 1975/06/25
公開日: 2008/11/18
ジャーナル フリーPyruvate decarboxylase [2-oxo acid carboxy-lyase, EC 4. 1. 1. 1] was isolated from sweet potato roots and was partially purified from healthy and diseased tissues. There was no appreciable difference in properties between the enzymes from healthy and diseased tissues. The molecular weight of the enzyme was found to be 240, 000 by polyacrylamide gel electrophoresis. Since sodium dodecyl sulfate polyacrylamide gel electrophoresis gave a molecular weight of 60, 000 for the monomeric form of the enzyme, it is likely that sweet potato pyruvate decarboxylase contains 4 single poly-peptide chains. The optimal pH of the decarboxylation reaction was 6.1-6.6. The Lineweaver-Burk double reciprocal plot curved upward, and the Hill coefficient was more than 1, with low concentrations of pyruvate. The enzyme was localized in the cytosol fraction. The activity of the enzyme increased in response to black-rot fungus infection, but decreased in response to cutting.抄録全体を表示PDF形式でダウンロード (1220K) -
V. Anomeric Forms of Maltose Produced in the Hydrolytic Reaction of Substituted Phenyl α-Maltosides Catalyzed by Saccharifying α-Amylase from B. subtilisToshio SHIBAOKA, Kiyoshi ISHIKURA, Keitaro HIROMI, Takehiko WATANABE1975 年 77 巻 6 号 p. 1215-1222
発行日: 1975/06/25
公開日: 2008/11/18
ジャーナル フリー1. Hydrolyses of phenyl α-maltoside and its derivatives with various substituents (P-NO2, p-Cl, p-CH3, p-C2H5, and p-C(CH3)3) catalyzed by saccharifying α-amylase from B. subtilis3 [EC 3. 2. 1. 1] were studied under conditions such that the products were only maltose and the corresponding phenols (1), in order to determine quan-titatively the anomeric form of the sugar produced from each substrate.
2. At the optimum pH of this enzyme (pH=5.4), maltose released from all the sub-stituted substrates studied was entirely in the β-form. These results are in remark-able contrast to the previous finding that α-maltose is exclusively produced from unsubstituted phenyl α-maltoside by this enzyme (2).
3. At pH 6.18 and 6.73, maltose produced from unsubstituted phenyl α-maltoside (φM) or p-tert-butylphenyl α-maltoside (PTBφM) was a mixture of α- and β-anomers, the ratio being dependent on pH as follows: For OM, the percentage of α-anomer was 100% (pH 5.4), 80% (pH 6.18), and 55% (pH 6.73), whereas for PTBgM, the percentage of /3-anomer was 100% (pH 5.4), 75% (pH 6.18), and 60% (pH 6.73).抄録全体を表示PDF形式でダウンロード (599K) -
Kunihiro UENO, Ineo ISHIZUKA, Tamio YAMAKAWA1975 年 77 巻 6 号 p. 1223-1232
発行日: 1975/06/25
公開日: 2008/11/18
ジャーナル フリーGlycolipids were purified from the total lipid extract of the testis or milt of a kind of puffer (Fugu rubripes rubripes) by adsorption column chromatography using silicic acid and magnesium silicate and by preparative silica gel TLC. The glycolipids were identified as glucosylceramide (116 μg/g wet tissue) and galactosylceramide (26.7 μg/g). Seminolipid, a sulfogalactolipid specific to mammalian testis was not detected, but the presence of a small amount of sulfatide (15.2 μg/g) was demonstrated. The long-chain bases of both cerebrosides were mainly C18-sphingenine, but in sulfatide, C20-sphingenine was more abundant than C18-sphingenine. In both cerebro-sides and sulfatide, the fatty acid compositions were similar, with nervonic acid as the predominant component.
Two species of gangliosides were also obtained and were identified as N-acetyl-galactosaminyl(1→44)[N-acetylneuraminyl(2→3)] galactosyl (1→4) glucosylceramide (59.8 μg/g) and N-acetylneuraminyl(2→3)galactosyl(1→4) N-ace tylglucosaminyl (1→3) gal-actosyl (1→4) glucosylceramide (45.0 μg/g). The long-chain bases of the two ganglio-sides consisted of C18-sphingenine and C20-sphingenine, and the major fatty acids were palmitic and stearic acids.抄録全体を表示PDF形式でダウンロード (1422K) -
Purification, Properties, and Mode of ActionNobuko KAWASAKI, Junko SUGATANI, Kunihiko SAITO1975 年 77 巻 6 号 p. 1233-1244
発行日: 1975/06/25
公開日: 2008/11/18
ジャーナル フリー1. Phospholipase B which hydrolyzes both the acyl ester bonds of diacylphospho-lipids (diacyl-hydrolase) and the acyl ester bond of monoacylphospholipids or lyso-phospholipids, [monoacyl-hydrolase or lysophospholipase, EC 3. 1. 1. 5] was purified from Penicillium notatum about 2000-fold over the crude extract. The final prepa-ration was homogeneous on disc electrophoresis. The apparent molecular weight, determined by gel filtration on Sephadex G-200, was about 116, 000. The isoelectric point was pH 4.0.
2. The purified enzyme was a glycoprotein. The carbohydrate content was appro-ximately 30%, consisting of mannose, glucose, and glucosamine. The amino acid composition was also determined.
3. The ratio of monoacyl-hydrolase to diacyl-hydrolase activities was influenced by the physical state of the substrate in the assay system. It was about 1:1 or 100:1 in the presence or absence of Triton X-100, respectively, and the latter value remained constant throughout the purification procedures.
4. Both enzyme activities had the same pH optimum, 4.0, and were heat-labile. None of the metals tested had any effect on either activity except for Felt and Fea+ Diisopropyl fluorophosphate at relatively high concentrations completely inhibited both enzyme activities. 5. The Michaelis-Menten constants (Km) of the enzyme for egg lecithin were about 1.5 and 25mm in the absence and presence of Triton X-100, respectively. The Km value for dicaproyllecithin was 9.8 mM and that for yeast lysolecithin was 0.054 mM in the absence of Triton X-100.
6. Using a mixture of 1-[14C]stearoyl-lecithin and 2-[14C]oleoyl-lecithin in the presence of Triton X-100 as a substrate, it was found that the P. notatum phospholipase B attacked the acyl ester bonds sequentially, first the 2-acyl and then 1-acyl groups.抄録全体を表示PDF形式でダウンロード (870K) -
Masako TANIGUCHI, Toshio SAKAGAMI1975 年 77 巻 6 号 p. 1245-1248
発行日: 1975/06/25
公開日: 2008/11/18
ジャーナル フリーPhospholipids in mitochondria can be exchanged with those in two microsomal fractions from rough endoplasmic reticulum (rough microsomes) and smooth endo-plasmic reticulum (smooth microsomes) in vitro in the presence of cell supernatant.
The amounts of phospholipids transferred from each submicrosomal fraction to mitochondria were slightly different. The compositions of the phospholipids trans-ferred to mitochondria from both microsomal fractions were the same, though these two fractions actually had different phospholipid compositions.抄録全体を表示PDF形式でダウンロード (277K) -
III. Circadian Rhythm in the KidneyKatsuya NAGAI, Mikio SUDA, Osamu YAMAGISHI, Yoshiko TOYAMA, Hachiro NA ...1975 年 77 巻 6 号 p. 1249-1254
発行日: 1975/06/25
公開日: 2008/11/18
ジャーナル フリーPhosphoenolpyruvate carboxykinase [EC 4. 1. 1. 32] activity in rat kidney shows a circadian rhythm with the highest activity between 0200 h and 0800 h and the lowest activity between 1400 h and 2000 h. The rhythm was observed in both sexes and throughout the year. Actinomycin D and cycloheximide effectively blocked the circadian increase in enzyme activity. These findings suggest that the circadian increase in phosphoenolpyruvate carboxykinase activity is due to net synthesis of enzyme protein through newly synthesized mRNA. In experiments with kidney cortex slices, gluconeogenesis from the radioactive precursor, [14C]malic acid, was considerably higher at 0200 h than at 1400 h, variyng in parallel with the change in the enzyme activity.抄録全体を表示PDF形式でダウンロード (426K) -
Takeshi TOMINAGA, Masatsugu KITAMURA, Yoshiko AZUMA, Tetsuo TAGUCHI, Y ...1975 年 77 巻 6 号 p. 1255-1259
発行日: 1975/06/25
公開日: 2008/11/18
ジャーナル フリーWhen prepared in the presence of deoxycholate, the activities for polypeptide synthesis of polysomes from normal and regenerating rat liver were similar. However, when the polysomes were prepared in the presence of either Triton X-100 or Lubrol WX, the polysomes from regenerating liver had about three to four times more activity than those from normal liver. On the other hand, the activities for polyphenylalanine synthesis of ribosomes from normal and regenerating rat liver were similar irrespective of whether these ribosomes were prepared in the presence of deoxycholate or Triton X-100.抄録全体を表示PDF形式でダウンロード (307K) -
V. Rifamycin Sensitivity of R17 RNA Synthesis In VivoSatomi J. IGARASHI, Frank B. ELLIOTT1975 年 77 巻 6 号 p. 1261-1269
発行日: 1975/06/25
公開日: 2008/11/18
ジャーナル フリーThe effect of rifamycin on R17 phage growth in vivo was examined using rifamycin sensitive and resistant strains of E. coli as host cells. The following conclusions were obtained: (1) There is a time lag between the addition of rifamycin to the culture and the initiation of inhibitory action by the drug. At 25 μg rifamycin per ml, this time lag is approximately 30 min. At 50 μg per ml, it takes 10 min to exert 90% inhibition of RNA synthesis in both infected and non-infected cultures. (2) The rifamycin sensitive stage for R17 growth is the first 20 min of its infectious cycle during which time the synthesis of phage components, but not the assembly, takes place. (3) Of the phage component synthesis, RNA synthesis is definitely sensitive to rifamycin in contrast to the other RNA phage systems, Of the four phage specific RNA's, progeny plus strand synthesis is strongly inhibited. The synthesis of replicating forms is also sensitive to rifamycin, but their suppression appears to be incomplete.抄録全体を表示PDF形式でダウンロード (747K) -
VI. A Large Scale Preparation of R17 Template RNASatomi J. IGARASHI1975 年 77 巻 6 号 p. 1271-1275
発行日: 1975/06/25
公開日: 2008/11/18
ジャーナル フリーA new procedure for R17 RNA preparation was devised using a 300 liters fermenter. The key factor in processing such a large quantity is the purification of phage par-ticles prior to RNA extraction. The method involves the preparation of 250 liters of crude lysate, condensation of phage particles by the partition method, purification by DEAE-cellulose column, and removal of adherent proteins by a series of high-salt washes. The method permits preparation of approximately 3g of phage particles free of ribosomal fragments and RNase. Phage RNA extracted in gram quantities using conventional methods often contain phenol. Thus repeated extraction of R17 RNA with salt-alcohol mixture is required.抄録全体を表示PDF形式でダウンロード (378K) -
I. Protein Ka with the Inv (3) Allotypic MarkerTomotaka SHINODA1975 年 77 巻 6 号 p. 1277-1296
発行日: 1975/06/25
公開日: 2008/11/18
ジャーナル フリーThe primary structure of the variable region of the human type K Bence-Jones Protein Ka with Inv(3) genetic marker was determined by sequence analysis of 25 major tryptic peptides covering 214 residues isolated from completely reduced and amino-ethylated protein. The complete sequences of 18 of these peptides were determined. These comprised the entire variable NH2-terminal half and 7 peptides from the COOH-terminal half of the protein, For the remaining peptides covering the COOH-terminus, only partial sequences or the amino acid compositions were determined. On the basis of these results all the tryptic peptides could be arranged in order. The sequence of the variable region differed from others previously reported in 21 to 51 residues, but no variation was found in the sequence of the last 107 residues. On the basis of sequence homology the protein was classified in the kI subgroup. A brief discussion of the possible genetic mechanism of sequence variability in relation to subgroup specificity is presented.抄録全体を表示PDF形式でダウンロード (1292K) -
Teruyoshi MATOBA, Etsushiro DOI1975 年 77 巻 6 号 p. 1297-1303
発行日: 1975/06/25
公開日: 2008/11/18
ジャーナル フリーThe substrate specificity of carboxypeptidase (F-II) purified from watermelon for various synthetic peptides and esters was examined kinetically. The enzyme showed a broad substrate specificity against various carbobenzoxy- and benzyl-dipeptides.. Peptides containing glycine or proline were hydrolyzed slowly by the enzyme. Peptides containing hydrophobic amino acids were hydrolyzed rapidly. The presence of hydrophobic amino acid residues, not only at the C-terminal position but also at the second position and probably the third position from the C-terminal resulted in an increase in the rate of hydrolysis.
Inhibition studies with diisopropyl fluorophosphate and diastereomers of carbo-benzoxy-Phe-Ala demonstrated that the peptidase and esterase activities of the enzyme are both catalyzed by the same site of the enzyme molecule, but the binding sites for peptides and esters seem not to be the same.
The enzyme also had amidase activity, which was optimal at pH 7.0抄録全体を表示PDF形式でダウンロード (480K) -
Daisuke TSURU, Mikio TOMIMATSU, Kunio FUJIWARA, Kazuo KAWAHARA1975 年 77 巻 6 号 p. 1305-1312
発行日: 1975/06/25
公開日: 2008/11/18
ジャーナル フリーAn inhibitor of neutral subtilopeptidase [EC 3. 4. 24. 4] was purified from porcine serum by salting out with (NH4)2SO4, chromatography on anion exchange Sephadex, gel filtration with Sepharose 6B, and isoelectric focusing. The preparation was homo-geneous by electrophoretic and ultracentrifugal criteria, and was shown to be a glycoprotein with a molecular weight of 740, 000. It inhibited the caseinolytic activities of thermolysin, subtilisin, trypsin [EC 3. 4. 21. 4], and α-chymotrypsin [EC 3. 4. 21. 1] as well as that of neutral subtilopeptidase by an equimolar binding to those proteolytic enzymes. SDS-polyacrylamide gel electrophoresis after reduction with β-mercaptoethanol indicated that the inhibitor was made up of four subunit monomers having a molecular weight of 190, 000. From comparisons of its physicochemical and inhibitory properties with those of well-investigated plasma proteins, the inhibitor was identified as α2-macroglobulin. On treatment of the inhibitor with neutral subtilopeptidase, a protein with a molecular weight of 95, 000 appeared after treatment with SDS and β-mercaptoethanol, suggesting that a peptide bond susceptible to the enzyme exists near the mid-point of the subunit chains.抄録全体を表示PDF形式でダウンロード (1205K) -
Rikimaru HAYASHI, Yasuo BAI, Tadao HATA1975 年 77 巻 6 号 p. 1313-1318
発行日: 1975/06/25
公開日: 2008/11/18
ジャーナル フリーThe metal content of carboxypeptidase Y was analyzed by the atomic absorption method. After exhaustive dialysis against an EDTA solution, the enzyme showed no loss of activity nor any significant content of metals (Zn, Mg, Ca, Cu, Mn, Ni, Fe, and Co). The activity was, however, rather sensitive to preincubation with various metals. The reactivity of a serine residue of the enzyme was also reevaluated. Diiso-propyl fluorophosphate (DFP) and phenylmethanesulfonyl fluoride (PMSF) stoichio-metrically and irreversively inhibited the enzyme. The rate of inactivation with DFP was much faster than that for trypsin [EC 3. 4. 21. 4] and chymotrypsin [EC 3. 4. 21. 1], while the rate with PMSF was one-fifteenth of that for chymotrypsin. The pH-dependence of the inactivation by DFP was similar to that of the enzymatic hydrolysis of acetylphenylalanine ethyl ester.
The present results indicate that carboxypeptidase Y is free of metals and has a serine residue with a vital role in the catalytic process, though the functional role of this SH group remains to be clarified.抄録全体を表示PDF形式でダウンロード (416K) -
V. Characterization of a Factor Repressing RNA Polymerase II as a RibonucleoproteinShunji NATORI, Kazuyuki TAKEUCHI, Den'ichi MIZUNO1975 年 77 巻 6 号 p. 1319-1323
発行日: 1975/06/25
公開日: 2008/11/18
ジャーナル フリーPreviously we reported the isolation of a factor, named the R-protein, which strongly repressed RNA polymerase II [EC 2. 7. 7. 6] of Ehrlich ascites tumor cells. In the present work this factor was found to contain much RNA (ratio of RNA to protein, 2.3 to 1). The RNA was G:C rich, with a very high content of guanylic acid (about 38%o).
On equilibrium density gradient centrifugation in Cs2SO4 solution, the RNA became distributed above free RNA, but after digestion of the R-protein with pronase the RNA cosedimented with free RNA. Thus the R-protein is a complex of RNA and Drotein.抄録全体を表示PDF形式でダウンロード (378K) -
Kazuei IGARASHI, Reiko KUROSAWA, Katsuko HARA, Seiyu HIROSE1975 年 77 巻 6 号 p. 1325-1333
発行日: 1975/06/25
公開日: 2008/11/18
ジャーナル フリーThe mechanism of inhibition of polypeptide synthesis by the addition of a tRNA fraction in a rat liver cell-free system was studied. The inhibition was found to occur at the step of aminoacyl-tRNA binding to ribosomes, in which aminoacyl-tRNA's were mainly responsible for the inhibition. The addition of EF-1 decreased the inhibition by the tRNA fraction. The tRNA fraction inhibited polypeptide synthesis in a polysome-S100 system under conditions in which poly U- and poly A-dependent polypeptide syntheses were not inhibited. The possibility that the amino-acyl-tRNA inhibitory activity functions through improper binding to the ribosomes in the polysome-S100 system is discussed.抄録全体を表示PDF形式でダウンロード (577K) -
Nobuo OKABE, Keiko SUYARI, Ken-ichi TOMITA1975 年 77 巻 6 号 p. 1335-1340
発行日: 1975/06/25
公開日: 2008/11/18
ジャーナル フリーThe effects of temperature and guanidine hydrochloride (GuHCl) on the fluorescence polarization of Y base in partially purified yeast phenylalanine tRNA (p.p.tRNAPhe) and in acriflavine conjugates of crude yeast tRNA were investigated to elucidate the stability of the conformation at the 3'-CpCpA terminus and the anticodon loop of tRNA. The results can be summarized as follows:
(1) The kinetic unit of the internal rotational motion near Y base in the anticodon loop of p.p.tRNAPhe seems to be independent of the temperature over the range 5-60°. Accelerated depolarization is observed in the 3'-CpCpA terminus at temperatures over 30°. This suggests that a change occurs in the native conformation of the 3'-CpCpA-acriflavine terminus at temperatures over 30°.
(2) The fluorescence polarization of Y base in p.p.t-RNAPhe is not affected by the addition of GuHC1 up to 6M, while that of acriflavine conjugated to the 3'-CpCpA terminus decreases markedly in the presence of 0.8 M GuHC1 reflecting the disruption of the native conformation.
These results indicate that the local conformation near Y base is stable, but that of the amino acid acceptor terminus is not.抄録全体を表示PDF形式でダウンロード (399K) -
α-Chymotryptic Hydrolysis of Derivatives of the Specific Substrates with Substituents in the NucleusMotonori OHNO, Shin-ichi SATO, Hiroshi MIZOGUCHI, Sadaji TSUKAMOTO1975 年 77 巻 6 号 p. 1341-1343
発行日: 1975/06/25
公開日: 2008/11/18
ジャーナル フリーSteady state kinetic studes of α-chymotrypsin [EC 3. 4. 21.l]-catalyzed hydrolysis of nucleus-substituted derivatives of the specific substrates were made at pH 6.5 and 7.8. Ac-Trp (NCps)-OMe was hydrolyzed more readily than Ac-Trp-OMe owing to its smaller Km value. The kcat values of Ac-Trp (CHO)-OMe and Ac-Tyr (3-NO2)-OMe were higher than those of the corresponding unmodified substrates, suggesting that derivatives with a substituent as large as a formyl or nitro group at the s-position are stereochemically favorable to the catalytic process. Derivatives of Ac-Phe-OMe with a chain of four atoms at the 3 or 4-position of the phenyl nucleus and 2, 3-dihydropyrrolo[2, 3-b]indoles derived from Ac-Trp-OMe were not hydrolyzed at all.抄録全体を表示PDF形式でダウンロード (220K) -
Hiroshi TAKEI, Yoko OTA, Ku Chayu WU, Tatsuo KIYOHARA, Genji MATSUDA1975 年 77 巻 6 号 p. 1345-1347
発行日: 1975/06/25
公開日: 2008/11/18
ジャーナル フリーAdult chicken hemoglobin is heterogeneous and contains two major components, AI and AII (1). The amino acid sequence of the a chain of the Al component from white leghorns (small A type) was determined and compared with that of the α chain of the AII component, previously determined by the authors (2). An unexpectedly large difference of 65 amino acids was found between these two chains.抄録全体を表示PDF形式でダウンロード (188K)
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