巻号一覧
111 巻, 6 号
選択された号の論文の22件中1～22を表示しています
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Junsei Taira, Kunio Mimura, Tohru Yoneya, Akifumi Hagi, Akira Murakami ...1992 年 111 巻 6 号 p. 693-695
発行日: 1992年
公開日: 2008/11/18
ジャーナル フリーTo elucidate the mechanism of sunlight-induced skin damage, guinea pigs were exposed to UV light (280-320nm, UV B, 4J/cm2) and a homogenate of the epidermis was examined by means of the thiobarbituric acid (TBA) test. Three hours after the exposure, TBA-malondialdehyde adducts had increased while glutathione reductase activity had decreased, indicating lipid peroxidation. To detect the initial species, spin trapping with 5, 5-dimethyl-1-pyrroline-N-oxide (DMPO) was applied to a suspension of illuminated epidermal cells (0.5J/cm2). An ESR signal obtained only with irradiation comprised a 1:2:2:1 quartet [a(N)=a(βH)=1.49mT] attributable to a spin adduct of hydroxyl radicals. These results suggest that sunlight exposure of skin may lead to hydroxyl radical generation and simultaneous lipid peroxidation.抄録全体を表示PDF形式でダウンロード (326K) -
Masayoshi Fukasawa, Hiroyuki Arai, Keizo Inoue1992 年 111 巻 6 号 p. 696-698
発行日: 1992年
公開日: 2008/11/18
ジャーナル フリーPlasma cholesteryl ester transfer protein (CETP) facilitates the net transfer and exchange of cholesteryl ester (CE), triglyceride (TG), and phospholipids between lipoproteins. A series of monoclonal antibodies (mAbs) against human CETP was obtained, comprising mAbs either inhibiting or not inhibiting these transfer activities. One mAb (LT-J1) inhibited the transfer activity of TG almost completely, but not that of CE, indicating that CE and TG binding sites on the CETP molecule may be distinct from each other, and that this mAb may specifically recognize the TG binding site. A radioimmunoassay system for determining the level of CETP was also established using these mAbs, and the plasma CETP levels in 20 normolipemic Japanese adults were found to range from 2.1 to 2.7mg/liter.抄録全体を表示PDF形式でダウンロード (1695K) -
Yasuzo Nishina, Kyosuke Sato, Kiyoshi Shiga, Shigeru Fujii, Kiyo Kurod ...1992 年 111 巻 6 号 p. 699-706
発行日: 1992年
公開日: 2008/11/18
ジャーナル フリーResonance Raman (RR) spectra of the complex of pig kidney medium-chain acyl-CoA dehydrogenase with acetoacetyl-CoA and of the purple complex formed upon the addition of octanoyl-CoA to the dehydrogenase were obtained. RR spectra were also measured for the complexes prepared by using isotopically labeled compounds, i.e., [3-13C]-, [1, 3-13C]-, and [2, 4-13C2] acetoacetyl-CoA; [1-13C] octanoyl-CoA; the dehydrogenase reconstituted with [4a-13C]- and [4, 10a-13C2] FAD. Both bands of oxidized flavin and acetoacetyl-CoA were resonance-enhanced in the 632.8nm excited spectra of the acetoacetyl-CoA complex; this confirms that the broad long-wavelength absorption band is a charge-transfer absorption band between oxidized flavin and acetoacetyl-CoA. The 1, 622cm-1 band was assigned to the C(3)=O stretching mode coupling with the C(2)-H bending mode of the enolate form of acetoacetyl-CoA and the bands at 1, 483 and 1, 119cm-1 were assigned to bands associated with the C(2)=C(1)-O- moiety. Both bands of fully reduced flavin and the substrate were resonance-enhanced in the 632.8nm excited spectra of the purple complex. As the enzyme is already reduced, the substrate must be oxidized to octenoyl-CoA; the complex is a charge-transfer complex between the reduced enzyme and octenoyl-CoA. The low frequency value of the 1, 577cm-1 band, which is associated with the C(2)-C(1)=O moiety of the octenoyl-CoA, suggests that the enzyme-bound octenoyl-CoA has an appreciable contribution of C(2)=C(1)-O-. The large contribution of ionic resonance structure, C(2)=C(1)-O-, for the ligands in both complexes, can be explained by the existence of an electrophilic group near the O atom of the C(1)=O group of the ligands and the electrostatic interaction between the group and the O atom of the ligand. This electrostatic interaction probably lowers the pKa value of a substrate at the C(2)-H in an early step of reductive half-reaction, facilitating the abstraction of the α-proton抄録全体を表示PDF形式でダウンロード (891K) -
Shin-ichi Tokishita, Atsuko Kojima, Takeshi Mizuno1992 年 111 巻 6 号 p. 707-713
発行日: 1992年
公開日: 2008/11/18
ジャーナル フリーEnvZ is a membrane-located protein kinase which modulates expression of the ompF and ompC genes through phosphotransfer signal transduction in Escherichia coli. Previously, we developed an in vitro method for analyzing the intact form of EnvZ in isolated cytoplasmic membranes, and demonstrated that this particular form of EnvZ exhibits the ability not only of OmpR phosphorylation but also OmpR dephosphorylation. Taking advantage of this in vitro system, in this study, to assess the structural and functional importance of the membrane-spanning (transmembrane) regions of EnvZ, a set of mutant envZ genes, each of which specifies a mutant EnvZ protein with a single amino acid replacement within or very near the transmembrane regions, were isolated and characterized in terms of their in vivo osmoregulatory phenotypes and in vitro EnvZ-OmpR phosphotransfer activities. On the basis of the results, it was suggested that the transmembrane regions of EnvZ play roles in transmembrane signaling and consequent modulation of the kinase/phosphatase activity exhibited by the cytoplasmic domain in response to an osmotic stimulus.抄録全体を表示PDF形式でダウンロード (2864K) -
Masao Takami, Izumi Kasuya, Hajime Tsunoo1992 年 111 巻 6 号 p. 714-721
発行日: 1992年
公開日: 2008/11/18
ジャーナル フリーThe polymerized albumin hypothesis was proposed for the mechanism of a hepatitis B virus (HBV) infection of human liver parenchymal cells on the basis that a receptor for polymerized albumin treated with glutaraldehyde was detected on isolated human liver parenchymal cells. However, some controversy exists regarding this hypothesis, because a receptor for formaldehyde-treated bovine serum albumin (f-BSA) has been found on liver non-parenchymal cells. Therefore, we characterized the uptake of polymerized rat serum albumin (p-RSA) and f-BSA by rat liver in vivo, and their bindings to liver cells in vitro. Most p-RSA and f-BSA was taken up by the liver after intravenous administration, and the uptake of p-RSA was inhibited by a 1, 000-fold excess of f-BSA. In addition, more than 80% of p-RSA taken up by the liver was found in the non-parenchymal cells, and the remainder was found in the parenchymal cells. P-RSA as well as f-BSA could bind to isolated rat liver parenchymal and non-parenchymal cells. Furthermore, p-RSA and f-BSA could bind to isolated rat liver cell plasma membranes, and these bindings were completely inhibited by 1, 000-fold excess of either f-BSA or p-RSA. These results indicate that there is a receptor, which can recognize both p-RSA and f-BSA, on not only rat liver non-parenchymal cells but also the parenchymal cells. It is also indicated that the receptor on the parenchymal cells as well as the non-parenchymal cells is involved in the in vivo uptake of p-RSA. These results are consistent with the polymerized albumin hypothesis, but an additional factor seems to be necessary for HBV to infect human liver parenchymal cells.抄録全体を表示PDF形式でダウンロード (969K) -
Hiroshi Kambe, Hiroaki Ito, Yoshihiro Kimura, Toshikazu Okochi, Hideo ...1992 年 111 巻 6 号 p. 722-725
発行日: 1992年
公開日: 2008/11/18
ジャーナル フリーGelsolin is a Ca2+-regulated actin-modulating protein found in a variety of cellular cytoplasm and also in blood plasma. Affinity separation of human plasma gelsolin was successfully accomplished by eluting the protein with a low concentration of nucleoside polyphosphate from immobilized Cibacron Blue F3GA (1, 2). This finding was followed by the demonstration that the protein had one class of ATP binding site with Kd=2.8×10-7M, which saturated at an ATP/gelsolin ratio of 0.6 in the absence of Ca2+ (3). To obtain further information on the nucleotide binding properties of gelsolin, binding studies were done in the presence of EGTA with GTP, ADP, and GDP by equilibrium dialysis. Incubation of plasma gelsolin with GTP resulted in binding of 0.6 mol of GTP per mol of protein with a dissociation constant of 1.8×10-6M, indicating that ATP binds to gelsolin with higher affinity than GTP. Neither ADP nor GDP at up to 100μM appreciably bound to gelsolin at a physiological salt concentration. Then, the effects of divalent metal ions on the ATP binding to plasma gelsolin were examined. Gelsolin bound to ATP with Kd=2.4×10-6M in a solution containing 2mM MgCl2, whereas micromolar free Ca2+ concentrations inhibited ATP binding. Furthermore, addition of Ca2+ rapidly reversed the preformed nucleotide binding to gelsolin, suggesting that Ca2+ binding to gelsolin leads to a conformational change which disrupts a nucleotide binding fold in the protein molecule.抄録全体を表示PDF形式でダウンロード (525K) -
Hideo Kubo, Gang Jung Jiang, Atsushi Irie, Masanori Morita, Toshiko Ma ...1992 年 111 巻 6 号 p. 726-731
発行日: 1992年
公開日: 2008/11/18
ジャーナル フリーGlucosylceramide (Glcβ1-1Cer) and a novel ceramide trihexoside (Galβ1-6Galβ1-6Glcβ1-1Cer) were purified from the eggs of the sea urchin, Hemicentrotus pulcherrimus. Their chemical structures were determined by gas-liquid chromatography, methylation analysis, chromic acid oxidation, enzymatic hydrolysis, enzyme-linked immunosorbent assay, fast atom bombardment mass spectrometry, and proton nuclear magnetic resonance spectroscopy. The ceramide trihexoside has a novel carbohydrate structure, and its core structure, Galβ1-6Glc, is also novel. The ceramide moieties of these glycolipids are almost identical. Two fatty acids, 22:1 and 22h:1, constitute more than 80% of the total acids. Long-chain bases are all phytosphingosine, approximately 90% of which is n-t18:0. The finding of melibiosylceramide (Galα1-6Glcβ1-1Cer) from the eggs of another sea urchin species [Kubo, H. et al. (1988) J. Biochem. 104, 755-760] and the present finding of the novel ceramide trihexoside suggest that there are a variety of unique sugar structures in sea urchin glycosphingolipids.抄録全体を表示PDF形式でダウンロード (904K) -
M. Yahiya Khan, Sudhir K. Agarwal, Sarfraz Ahmad1992 年 111 巻 6 号 p. 732-735
発行日: 1992年
公開日: 2008/11/18
ジャーナル フリーEffect of pH, urea, and guanidine hydrochloride on the activity and structure of buffalo spleen cathepsin B was investigated. At alkaline pH, there was an irreversible loss of the structure as well as the activity of the buffalo enzyme. At acidic pH, however, the inactivation of the enzyme was reversible. The enzyme reversibly lost most of its activity at denaturant concentrations which did not cause a significant change in its secondary structure. The inactivation could be attributed to minor perturbations in the environment of the amino acid residue(s) at and/or around the active site of the enzyme. High urea/guanidine hydrochloride concentrations leading to the structural changes in cathepsin B made the inactivation process irreversible.抄録全体を表示PDF形式でダウンロード (465K) -
Xiang Zhao, Kimi Araki, Jun-ichi Miyazaki, Ken-ichi Yamamura1992 年 111 巻 6 号 p. 736-738
発行日: 1992年
公開日: 2008/11/18
ジャーナル フリーTransgenic mice were produced by microinjection of a human serum amyloid P component (hSAP) gene or a fusion gene (SS) comprising the promoter for hSAP (nucleotides -600 to -14 from the start codon) and the coding region of the hepatitis B virus surface antigen (HBsAg). In adult mice, both transgenes were expressed only in the liver, and thus the pattern of expression resembled that of the endogenous mouse SAP gene. Both hSAP mRNA and HBsAg were first detected in liver on the second postnatal day. The level of these products increased rapidly and reached the maximum within the first week. These results suggest that the hSAP gene contains a short, cis-acting, developmental, and liver-specific regulatory sequence at the 5' or the 3' end and that this sequence can target expression of the foreign gene.抄録全体を表示PDF形式でダウンロード (620K) -
Kazunobu Matsushita, Kazuhiro Takahashi, Motohisa Takahashi, Minoru Am ...1992 年 111 巻 6 号 p. 739-747
発行日: 1992年
公開日: 2008/11/18
ジャーナル フリーAcetobacter methanolicus is a unique acetic acid bacterium which has a methanol oxidase respiratory chain, as seen in methylotrophs, in addition to its ethanol oxidase respiratory chain. In this study, the relationship between methanol and ethanol oxidase respiratory chains was investigated. The organism is able to grow by oxidizing several carbon sources, including methanol, glycerol, and glucose. Cells grown on methanol exhibited a high methanol-oxidizing activity and contained large amounts of methanol dehydrogenase and soluble cytochromes c. Cells grown on glycerol showed higher oxygen uptake rate and dehydrogenase activity with ethanol but little methanol-oxidizing activity. Furthermore, two different terminal oxidases, cytochrome c and ubiquinol oxidases, have been shown to be involved in the respiratory chain; cytochrome c oxidase predominates in cells grown on methanol while ubiquinol oxidase predominates in cells grown on glycerol. Both terminal oxidases could be solubilized from the membranes and separated from each other. The cytochrome c oxidase and the ubiquinol oxidase have been shown to be a cytochrome co and a cytochrome bo, respectively. Methanol-oxidizing activity was diminished by several treatments that disrupt the integrity of the cells. The activity of the intact cells was inhibited with NaCl and/or EDTA, which disturbed the interaction between methanol dehydrogenase and cytochrome c. Ethanol-oxidizing activity in the membranes was inhibited with 2-heptyl-4-hydroxyquinoline N-oxide, which inhibited ubiquinol oxidase but not cytochrome c oxidase. Alcohol dehydrogenase has been purified from the membranes of glycerol-grown cells and shown to reduce ubiquinone-10 as well as a short side-chain homologue in detergent solution. Furthermore, the ethanol oxidase respiratory chain was reconstituted into proteoliposomes containing alcohol dehydrogenase together with ubiquinone-10 and cytochrome bo. Thus, the results obtained in this study suggest that A. methanolicus has two independent respiratory chains for methanol and ethanol. The methanol oxidase respiratory chain appears to operate by linking methanol dehydrogenase to cytochrome c oxidase, cytochrome co, via soluble cytochrome(s) c, while the ethanol oxidase respiratory chain consists of alcohol dehydrogenase, ubiquinone, and cytochrome bo ubiquinol oxidase.抄録全体を表示PDF形式でダウンロード (2475K) -
Tsuyoshi Takasuka, Nobutake Akiyama, Ikuo Horii, Yasuhiro Furuichi, Ta ...1992 年 111 巻 6 号 p. 748-753
発行日: 1992年
公開日: 2008/11/18
ジャーナル フリーThere are at least two types of endothelin receptors, ETA and ETB, present in various tissues. We found that although biotinylated ET-1 could bind to both ETA and ETB receptors, the stability of the formed ligand-receptor complexes was different. When the preformed complexes of receptor (solubilized from canine brain and lung membranes) and biotinylat-ed ET-1 were subjected to avidin agarose column chromatography, most of the ETA activity was recovered in the pass-through fraction and the remainder was recovered in the 0.5M KSCN eluate as ligand-free forms. On the other hand, the ETB activity bound firmly to the avidin agarose column was eluted with 1.5M KSCN. The detection of the complex of 125I-ET-1 and its receptor by SDS-PAGE run at a low temperature was only possible with the ETB fractions and the complex of 125I-ET-1 and ETA was unstable during the separation. These results suggest that the conformation of the ligand binding sites of canine ETA and ETB as well as the stability of their ligand-receptor complexes to SDS are significantly different. Similar observations were also obtained for human ETA and ETB receptors.抄録全体を表示PDF形式でダウンロード (1792K) -
Hisashi Hirano, Setsuko Komatsu, Hikaru Takakura, Fumio Sakiyama, Susu ...1992 年 111 巻 6 号 p. 754-757
発行日: 1992年
公開日: 2008/11/18
ジャーナル フリーA method was developed for direct microsequencing of Nα-acetylated proteins electroblotted onto polyvinylidene difluoride membranes from polyacrylamide gels. Nα-Acetylated proteins (>32pmol), including horse heart cytochrome c, five mutants of yeast cytochrome c, and bovine erythrocyte superoxide dismutase, were separated by SDS-PAGE and electroblotted onto polyvinylidene difluoride membranes. The portions of the membrane carrying the bands were cut out and treated with 0.5% polyvinylpyrrolidone in acetic acid solution at 37°C for 30min. The protein was digested on the membrane with 5-10μg of trypsin at 37°C for 24h. During tryptic digestion, the resultant peptides were released from the membrane and the N-terminal peptide was efficiently deblocked with 50mU of acylamino acid-releasing enzyme at 37°C for 12h. Picomole levels of the deblocked proteins could be sequenced directly by use of a gas-phase protein sequencer.抄録全体を表示PDF形式でダウンロード (389K) -
Saeko Takada, Hitoshi Sakakibara, Ritsu Kamiya1992 年 111 巻 6 号 p. 758-762
発行日: 1992年
公開日: 2008/11/18
ジャーナル フリーA procedure was developed for isolating Chlamydomonas outer-arm dynein that can functionally combine with the axoneme of an outer-arm-missing mutant, oda1. Previous studies showed that the outer-arm dynein of this organism, containing three heavy chains (α, β, γ), dissociates upon extraction with a high-salt-concentration buffer solution into an 18-S particle containing the α and β heavy chains and a 12-S particle containing the γ heavy chain. It was found, however, that the three heavy chains did not dissociate if the high-salt extract was centrifuged in the presence of Mg2+; the three chains constituted a single species (23-S dynein) sedimenting at about 23 S and displayed a three-headed bouquet configuration in electron micrographs. Furthermore, the 23-S dynein had the activity to bind to the axonemes of oda1 and increase the reactivated motility of detergent-extracted cell models; its addition increased the beat frequency from 28Hz to 53Hz, a frequency comparable to that of wild-type axoneme. The 18-S and 12-S dyneins, on the other hand, were unable to increase the motility of oda1 axonemes even when added together. The new protocol thus enables purification of outer-arm dynein that retains its functional activity. It will provide a useful experimental system with which to study the mechanism of outer-arm function.抄録全体を表示PDF形式でダウンロード (3009K) -
Issay Okazaki, Masaru Himeno, Junji Ezaki, Toyoko Ishikawa, Keitaro Ka ...1992 年 111 巻 6 号 p. 763-769
発行日: 1992年
公開日: 2008/11/18
ジャーナル フリーSialoglycoprotein with a molecular mass of 85kDa (LGP85) was purified from rat liver lysosomal membranes with a 0.9% recovery to apparent homogeneity, as determined from the pattern on polyacrylamide gel electrophoresis in the presence and in the absence of SDS. The purification procedures included: preparation of lysosomal membranes, elimination of LGP107 and LGP96 with immunoaffinity columns, WGA-Sepharose affinity chromatography, hydroxylapatite chromatography, and preparative polyacrylamide gel electrophoresis. LGP85 contains about 22.8% carbohydrate and the carbohydrate moiety is composed of mannose, galactose, fucose, glucosamine, galactosamine, and neuraminic acid, in a molar ratio of 40:20:2:23:3:13. Susceptibility to neuraminidase and immunoreactivity of the protein in intact tritosomes were examined to study the topology of the protein in tritosomal membranes. Neuraminidase susceptibility and immunoreactivity of the protein were not observed in intact tritosomes until the tritosomes had been disrupted by osmotic shock. These observations suggest that both oligosaccharide chains and the main protein portion of the protein are located on the interior surface of the tritosomal membranes. Subcellular localization of LGP85 was determined using enzyme immunoassay. The lysosomes seem to be the major location. LGP85 in the lysosomes was divided into the membrane bound form (90%) and the soluble form (10%). Immunoelectron microscopy clearly confirmed that the localization of LGP85 is mainly confined to lysosomes.抄録全体を表示PDF形式でダウンロード (6019K) -
Takahiro Kyouden, Masaru Himeno, Toyoko Ishikawa, Yukihide Ohsumi, Kei ...1992 年 111 巻 6 号 p. 770-777
発行日: 1992年
公開日: 2008/11/18
ジャーナル フリーDipeptidyl peptidase IV (m-DPP IV) in rat liver lysosomal membranes was purified about 50-fold over the lysosomal membranes with 38% recovery to apparent homogeneity, as determined from the pattern on polyacrylamide gel electrophoresis in the presence and in the absence of SDS. The enzyme amounts to about 3% of lysosomal membrane protein constituents. The purification procedures included: extraction of lysosomal membranes by Triton X-100, WGA-Sepharose affinity chromatography, hydroxylapatite chromatography, ion exchange chromatography, and preparative polyacrylamide gel electrophoresis. The enzyme (Mr, 240, 000) is composed of two identical subunits with an apparent molecular weight of 110, 000. The enzyme contains about 12.4% carbohydrate and the carbohydrate moiety was composed of mannose, galactose, fucose, N-acetylglucosamine, and neuraminic acid in a molar ratio of 14:17:2:24:11. Susceptibility to neuraminidase and immunoreactivity of the enzyme in intact tritosomes were examined to study the topology of the enzyme in tritosomal membranes. Neuraminidase susceptibility and immunoreactivity of the enzyme were not observed in the intact tritosomes until the tritosomes had been disrupted by osmotic shock. This result indicated that both the oligosaccharide chains and the main protein portion of the enzyme are on the inside surface of the tritosomal membranes. Subcellular localization of DPP IV was determined by means of enzyme immunoassay, which indicated that bile canalicular membranes and lysosomal membranes are the major sites of localization, and DPP IV activity in lysosomes was separated into a membrane bound form (60%) and a soluble form (40%). Immunoelectron microscopy clearly confirmed that DPP IV occurs not only in the bile canalicular domain but also in the lysosomes of rat liver.抄録全体を表示PDF形式でダウンロード (4816K) -
Koui Takahashi, Akihito Hattori, Ryuichi Tatsumi, Kouji Takai1992 年 111 巻 6 号 p. 778-782
発行日: 1992年
公開日: 2008/11/18
ジャーナル フリーWhen rabbit skeletal muscle myofibrils were treated with a solution containing 0.1mM Ca2+ and 30μg of leupeptin/ml, α-connectin, which forms very thin filaments in myofibrils, was split into β-connectin and a 1, 200-kDa subfragment. Apart of β-connectin located near the junction between β-connectin and the subfragment seems to have an affinity for calcium ions and to be susceptible to the binding of large amounts of calcium ions. The calcium-binding site on β-connectin is localized near the N2 line in the I band, and the subfragment is localized adjacent to the Z disk. It is possible that connectin filaments change their elasticity during the contraction-relaxation cycle of skeletal muscle at the physiological concentration of calcium ions. Because postmortem skeletal muscles lose their elasticity and become plastic in association with the calcium-specific splitting of connectin filaments, the splitting is considered to be a factor in meat tenderization during postrigor ageing.抄録全体を表示PDF形式でダウンロード (4310K) -
Tatsuo Kurihara, Mitsuyoshi Ueda, Hirofumi Okada, Naomi Kamasawa, Nobu ...1992 年 111 巻 6 号 p. 783-787
発行日: 1992年
公開日: 2008/11/18
ジャーナル フリーWhen an n-alkane-utilizable yeast, Candida tropicalis pK233, was cultivated on butyrate, the fatty acid of shortest chain-length for β-oxidation, as the sole source of carbon and energy, catalase and the enzymes of the fatty acid β-oxidation system were inducibly synthesized at high levels. As in the alkane-grown cells, the proliferation of peroxisomes was harmonized with the induction of peroxisomal enzymes. The results of subcellular fractionation and immunoelectronmicroscopy indicated the localization of these enzymes in peroxisomes, not in mitochondria. It was suggested that only peroxisomes have a role in fatty acid, β-oxidation in the yeast cells, unlike in mammalian cells, in which cooperation between peroxisomes and mitochondria is essential.抄録全体を表示PDF形式でダウンロード (2619K) -
Fumito Takeuchi, Eikichi Hashimoto, Hirohei Yamamura1992 年 111 巻 6 号 p. 788-792
発行日: 1992年
公開日: 2008/11/18
ジャーナル フリーIn regenerating rat liver, nuclear protein histone H2A was shown to be phosphorylated on its amino-terminal serine residue [Sung et al. (1971) J. Biol. Chem. 246, 1358-1364], but the protein kinase which phosphorylates this residue has not been identified. To evaluate the possibility that protein kinase C can phosphorylate this residue, calf thymus histone H2A was 32P-labeled by incubation with [γ-32P] ATP and highly purified protein kinase C from rat brain in the presence of calcium and phospholipid. About 1 mol of 32P was incorporated per mol of histone H2A and the Km and apparent Vmax of the reaction were calculated to be 2.1μM and 0.35μmol/min/mg, respectively. So histone H2A seemed to be a good substrate for protein kinase C. Further, the proteolytic phosphopeptides of 32P-labeled histone H2A were isolated by means of a series of column chromatographies and analyzed for their amino acid compositions. Comparison of the data with the known primary structure of histone H2A revealed their amino acid sequence as 1Ser-Gly-Arg. These data suggest that protein kinase C may be a candidate for the protein kinase which phosphorylates the amino-terminal serine residue of histone H2A during the regeneration of rat liver.抄録全体を表示PDF形式でダウンロード (487K) -
Kazuo Yamamoto, Chan Ching Yee, Masahiro Shirakawa, Yoshimasa Kyogoku1992 年 111 巻 6 号 p. 793-797
発行日: 1992年
公開日: 2008/11/18
ジャーナル フリーTo investigate the mechanism of DNA recognition by the homeodomain, truncated proteins containing the entire homeodomain encoded by the Drosophila engrailed gene were expressed in Escherichia coli. Each protein was accumulated to an amount representing more than 40% of the total bacterial protein and recovered in the soluble fraction. Of the three truncated proteins, the shortest one (71 amino acid residues) was further purified by conventional chromatography. The purified engrailed homeodomain (En-HD) protected a DNA sequence, TTAATT, the core element of consensus sequences recognized by many other homeodomain proteins, from DNase I digestion. UV-CD spectra of the En-HD showed that it mainly consisted of α-helix. Based on one-dimensional 1H-NMR spectra, the tertiary structure of the En-HD was shown to be stable against temperature up to 50°C and low pH. The low pH resistancey of the protein was also demonstrated by UV-CD measurement. Thus, the current over-production system provides an active and stable homeodomain, which is suitable for structure-function analysis.抄録全体を表示PDF形式でダウンロード (890K) -
Yasushi Hasegawa, Yoshihisa Ueda, Michitoshi Watanabe, Fumi Morita1992 年 111 巻 6 号 p. 798-803
発行日: 1992年
公開日: 2008/11/18
ジャーナル フリーAmino acid sequences were analyzed for two isoforms of myosin essential light chain, LC17a and LC17b [Hasegawa, Y., Ueno, H., Horie, K., & Morita, F. (1988) J. Biochem. 103, 15-18] from porcine aorta smooth muscle. Both LC17a and LC17b consisted of 150 amino acid residues and their N-terminal Cys residues were blocked by an acetyl group. The amino acid sequences of LC17a and LC17b were common from the N-terminal to Glu-141 and five amino acid substitutions were observed within the remaining C-terminal 9 residues. The amino acid sequences of LC17a and LC17b were identical to those deduced from the nucleotide sequences of bovine aortic cDNAs encoding the two isoforms [Lash, J. A., Helper, D. J., Klug, M., Nicolozakes, A. W., & Hathaway, D. R. (1990) Nucleic Acids Res. 18, 7176].抄録全体を表示PDF形式でダウンロード (600K) -
Yasushi Hasegawa, Fumi Morita1992 年 111 巻 6 号 p. 804-809
発行日: 1992年
公開日: 2008/11/18
ジャーナル フリーAorta smooth muscle myosin contains two kinds of 17-kDa essential light chain, LC17nm (nonmuscle-type) and LC17gi (gizzard-type) [Hasegawa, Y., Ueda, Y., Watanabe, M., & Morita, F. (1992) J. Biochem. 111, 798-803]. The LC17 isoforms were released from porcine aorta myosin by incubation at 46°C. The rate of release was 1.5 to 2 times higher with LC17gi than with LC17nm. Aorta myosins containing the two LC17 isoforms in various ratios could be reconstituted. The actin-activated ATPase activity was measured as a function of LC17nm content. The Vm value was lower with myosin which contained more LCl7nm. The apparent dissociation constant for F-actin, Km, was 20-fold less with myosin which contained 81% LCl7nm than myosin which contained 23% LC17nm. A similar difference in the dissociation constants of myosin for F-actin was observed in the presence of adenylyl imidodiphosphate. The role of LC17nm appears to be to make aorta myosin suitable for maintaining the muscle tension with a low expenditure of energy. The isoform-dependent difference in the F-actin-binding affinities of myosin seems partly due to the difference in the affinities of LC17 isoforms themselves for F-actin. We found that the isolated LCl7nm itself could bind with F-actin with a dissociation constant of 64μM, but LC17gi could not. The C-terminal region where the amino acid residues are substituted in the two isoforms [Hasegawa, Y., Ueda, Y., Watanabe, M., & Morita, F. (1992) J. Biochem. 111, 798-803; Lash, J. A., Helper, D. J., Klug, M., Nicolozakes, A. W., & Hathaway, D. R. (1990) Nucleic Acids Res. 18, 7176] appears to be involved in actin-binding, heavy chain-binding, and ATPase activity.抄録全体を表示PDF形式でダウンロード (1162K) -
1992 年 111 巻 6 号 p. 810
発行日: 1992年
公開日: 2008/11/18
ジャーナル フリーPDF形式でダウンロード (17K)
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