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Y Ohmiya

Publications and source records attributed to Y Ohmiya.

At least 37 records · Page 2Linked to original sources
PubMed1993

Cloning, expression and sequence analysis of cDNA for the Ca(2+)-binding photoprotein, mitrocomin.

The primary structure of mitrocomin consists of 190 amino acid residues, with three Ca(2+)-binding sites and a tyrosine residue at the C-terminus. Mitrocomin shows an amino acid sequence homology of 67.9% and 60.7% when compared with aequorin and clytin, respectively. The amino acid residues Cys152, His58, His169, Trp12, Trp86, Trp108, Trp129 and Trp173 are conserved in all three photoproteins, suggesting that they play a role in light emission.

Aequorin↗
PubMed1993

Mass spectrometric evidence for a disulfide bond in aequorin regeneration.

Tryptic digests of purified recombinant apoaequorin were analyzed, before and after reduction with DTT, by fast atom bombardment mass spectrometry. The results showed that apoaequorin contains a disulfide bond between Cys145 and Cys152 and that the reduction of this bond is involved in the regeneration of aequorin.

Aequorin↗
PubMed1993

Bioluminescence of the Ca(2+)-binding photoprotein, aequorin, after histidine modification.

Modification studies of the 5 histidine residues in aequorin employing site-directed mutagenesis and diethyl pyrocarbonate suggested that His169 may be the site of binding of molecular oxygen in aequorin. The modification of this residue led to complete loss of activity, whereas modification of the remaining 4 histidine residues yielded mutant aequorins with varying bioluminescence activities.

Aequorin↗
PubMed1993

Microvascular reconstruction of nose and ear defects using composite auricular free flaps.

Two cases using composite auricular free flaps, based on the superficial temporal vessels, in the reconstruction of full-thickness defects of the nose and ear are reported. This composite free flap can be based on either the superficial temporal or the posterior auricular vessels depending on the defect to be reconstructed. The superficial temporal vessels can also be used in reversed flow to obtain a vascular pedicle of sufficient length for microvascular anastomosis. The anatomical vascular features of the flap make it possible to reconstruct various facial defects with freedom of design.

Adult↗
PubMed1993

[Analgesic effect of benzoylmesaconine].

"Tsumura Shuchi-Bushi Powder for Ethical Dispensing" (TJ-3021) is an herbal drug of processed Aconiti tuber that attenuates its toxicity. A greater part of mesaconitine which is regarded as a main analgesic component in processed Aconiti tuber is hydrolyzed into benzoylmesconine (BM) by its processing. In this study, the analgesic effect of BM was examined in comparison with that of TJ-3021 in mice and rats. BM (10 mg/kg, p.o.) depressed the acetic acid-induced writhing significantly. Its analgesic activity was almost similar in magnitude to that of TJ-3021 (300 mg/kg, p.o.). BM (30 mg/kg, p.o.) significantly increased the pain threshold ratio of paw pressure in repeated cold stress (RCS) rats, and its analgesic potency appeared to be equivalent to that of TJ-3021 (1000 mg/kg, p.o.). These results suggest that the analgesic activity of BM is strong enough for explanation of the analgesic effect of TJ-3021, and it might contribute to that of TJ-3021.

Aconitine↗
PubMed1992

Imaging of luciferase secretion from transformed Chinese hamster ovary cells.

The blue luminescence characteristic of the marine ostracod crustacean Vargula hilgendorfii is from a simple, but highly specific, enzyme-substrate reaction. Light is emitted by the oxidation of Vargula luciferin (substrate) by molecular oxygen, a reaction catalyzed by luciferase. Stable transformants of Chinese hamster ovary cells carrying the Vargula luciferase gene secreted luciferase from discrete sites on the cell surface, and this secretion could be monitored in real time by the bioluminescence produced by the secreted luciferase in the presence of Vargula luciferin by using an image-intensifying technique. Addition of anti-Vargula luciferase IgG to the luminescing cells almost completely extinguished the luminescence, confirming that Vargula luciferase caused the luminescence.

Animals↗
PubMed1992

Two excited states in aequorin bioluminescence induced by tryptophan modification.

The Ca(2+)-activated photoprotein, aequorin, contains six tryptophan residues and has a bioluminescence emission maximum at 465 nm. On converting the six tryptophan residues to phenylalanine, the mutant aequorins exhibited varied luminescence activities and spectra, but one mutant, with tryptophan-86 replaced by phenylalanine, gave a bimodal emission spectrum, with maxima at 455 nm and 400 nm. This result suggests that tryptophan-86 may be importantly involved in the generation of the product excited state during aequorin bioluminescence.

Aequorin↗
PubMed1991

A C-terminal proline is required for bioluminescence of the Ca(2+)-binding photoprotein, aequorin.

The requirement for a proline residue at the C-terminus of the Ca(2+)-binding photoprotein, aequorin, was investigated by measuring luminescence activities of a series of C-terminal deletion mutants, substitution mutants and an addition mutant. CD spectral measurements of apoaequorin with the C-terminal proline deleted showed a small change in secondary structure. In all cases studied, the C-terminal proline was required for bioluminescence activity.

Aequorin↗
PubMed1991

Tyrosine-130 in bullfrog thyroglobulin is a thyroid hormone generating site.

Bullfrog thyroglobulin was digested with lysyl endopeptidase, known to be highly specific to cut the C-terminal side of lysine residue in protein, after reduction and carboxymethylation. We isolated one peptide which lacked the C-terminal lysine, and which corresponds to 103-129 of bovine thyroglobulin sequence. Tyrosine 130 in the mammalian thyroglobulin molecule is known to be an iodination site. These findings suggest that tyrosine 130 in frog thyroglobulin is a thyroid hormone generating site.

Amino Acid Sequence↗
PubMed1990

Separation of DNA fragments by high-resolution ion-exchange chromatography on a nonporous QA column.

A nonporous QA column (a strong anion exchanger) was used for HPLC of DNA fragments. This column was successfully employed to separate small (ca. 10 bp) and intermediate size (ca. 10 kbp) DNA fragments from each other. The column also separated double-stranded DNA from its single-stranded form, and circular DNA molecules from linear ones. The entire separation process was completed within 60 min. The recovery of DNA fragments in each run was above 95%. High resolution was obtained both at an analytical level (microgram scale) and at a preparative level (100 micrograms scale). In view of time efficiency, recovery, and resolution, the nonporous QA column is superior to other porous ion-exchange columns and expected to be a very useful tool in molecular biological studies.

Anions↗
PubMed1990

Location of dehydroalanine residues in the amino acid sequence of bovine thyroglobulin. Identification of "donor" tyrosine sites for hormonogenesis in thyroglobulin.

Thyroid hormonogenesis in thyroglobulin results in the conversion of an "acceptor" iodotyrosine to a hormone residue and a "donor" iodotyrosine to a dehydroalanine residue. Altogether five acceptor sites have been located as hormone residues in thyroglobulin of different animal species. To search for donor sites, we treated bovine thyroglobulin with 4-aminothiophenol to specifically modify dehydroalanine residues to S-(4-aminophenyl)cysteine (APC) residues, according to the principle of dehydroalanine determination developed by us (Kondo, T., Kondo, Y., and Ui, N. (1988) Mol. Cell. Endocr. 57, 101-106). After digesting thyroglobulin with lysyl endopeptidase, APC-containing peptides were separated from other peptides by trapping them on immobilized naphthylethylenediamine and from each other by size-exclusion and reverse-phase high performance liquid chromatography (HPLC). The HPLC patterns showed about 10 APC-containing peptides. Among them, four different peptides were purified by repeated reverse-phase HPLC. The results of partial sequencing of the four peptides by manual Edman degradation disclosed that Tyr5, Tyr926, Tyr1375, and Tyr986 or Tyr1008 are available for hormonogenesis as donor sites. These results strongly suggest that only specific tyrosine residues behave as donors.

Alanine↗
PubMed1989

Isolation and characterization of hagfish thyroid iodoprotein by its non-thyroglobulin nature, very high iodine and carbohydrate contents and low hormone/iodine ratio.

We have characterized the thyroid iodoprotein of a hagfish, Eptatretus burgeri, one of the lowest marine vertebrates. The iodoprotein was not very homogeneous in its apparent molecular mass which decreased with the increase in hormone/iodotyrosine ratio. Four subfractions with an apparent molecular mass of about 400 kDa were purified from one major fraction by size-exclusion and Mono Q ion-exchange HPLC. The subfractions appeared to have the same peptide backbone, since they showed a single band with the same mobility as a 160-kDa protein in SDS/PAGE and the same amino acid composition. However they differed from each other in having increasing iodine contents (1.9% to 5.9% by mass of total amino acids) associated with the increase in hormonal iodine proportion (8.4% to 16.7% of total iodine) and carbohydrate content (35.6% to 53.5% by mass). These values are strikingly different from those of thyroglobulin with an iodine content of less than 1%, hormonal iodine of 20-40% and carbohydrate content of less than 10%. The amino acid composition of the hagfish iodoprotein, especially the cysteine content of less than 1%, was also entirely different from that of thyroglobulin. These results suggest that most, if not all, tyrosine residues of the hagfish thyroid glycoprotein with a less rigid structure are susceptible to an iodinating system, but hormone residues are formed by a much less efficient mechanism than those in thyroglobulin, when poorly iodinated.

Amino Acids↗
PubMed1989

Influence of food on bioavailability from two controlled-release granules of theophylline.

The bioavailability and absorption pattern of theophylline from Theolong granule and Theodur-G were studied in five healthy volunteers both in fasting conditions and after taking two different meals. In all the subjects, no dose-dumping effect was observed with a standard- or a fat-rich breakfast on these preparations. Postprandial administration delayed the absorption of theophylline and a fat-rich breakfast significantly reduced the area under the curve (AUC0-26) for both preparations. The mean AUC decreased by 14.0% for the former and 19.7% for the latter when the fat-rich breakfast was administered. Intake of a standard breakfast resulted in a decrease in the AUC0-26 by 10.6% for Theolong granules but there was little effect observed with the Theodur-G granules.

Adult↗
PubMed1988

Evidence for a preferential iodination site within the thyroglobulin molecule.

Mouse 330 kDa thyroglobulin labeled in vivo was analyzed using a tryptic peptide mapping technique and high performance liquid chromatography (HPLC). 30 min after Na125I injection, one peptide spot (spot 7) on a silica gel plate was the only prominent labeled peptide, followed by other labeled peptide spots after 1 h. HPLC showed that spot 7 was rich in monoiodotyrosine. The ratios between the iodoamino acids were strictly maintained from 1 to 6 h after Na125I injection. Spot 7 was again the first spot that appeared from the samples of iodine-deficient mice. These data indicate that there is some preferential iodination site(s) within the thyroglobulin molecule and also that their iodoamino acid composition is predetermined.

Amino Acids↗
PubMed1988

Preferential formation of triiodothyronine residues in newly synthesized [14C]tyrosine-labeled thyroglobulin molecules in follicles reconstructed in a suspension culture of hog thyroid cells.

Early processes of thyroid hormone (T4 and T3) synthesis in thyroglobulin molecules were studied using follicles reconstructed in a primary culture of hog thyroid cells under the influence of TSH. When the reconstructed follicles were incubated with 14C-tyrosine, thyroglobulin containing the labeled tyrosine was newly synthesized and in the presence of iodide, some of the labeled tyrosine residues were iodinated and coupled to produce labeled iodothyronines, T4 and T3. Coupling efficiency, especially the efficiency of T3 production, was much higher than that obtained from the average iodoamino acid composition of mature thyroglobulin from the gland, indicating a preferential iodination of hormonogenic tyrosines and synthesis of T3. The total production of T3 was higher than T4 under the present conditions. However, free labeled T4 released into the medium was more than T3 after 16 h incubation of the labeled follicles with non-labeled tyrosine, suggesting the preferential liberation of T4 from the labeled peptide and/or release from the cells.

Animals↗
PubMed1985

Comparison of pulmonary accumulation of pyrilamine and pyrilamine N-oxide.

Our previous studies have indicated that a phenothiazine drug, chlorpromazine, and a tricyclic antidepressant, imipramine, are metabolized by the isolated perfused rat lungs via N-oxidation from whence their N-oxides are released into the circulation. This work was undertaken to compare the pulmonary accumulation of another pneumophilic tertiary amine drug, pyrilamine, with that of its N-oxide. Approximately 10-fold greater accumulation of pyrilamine than that of its N-oxide was observed in the mouse lung after a single pass perfusion with 40 microM of the drug for a 3 min period. The largest difference between accumulation of pyrilamine and its N-oxide was noted in the lung among the various tissue slices tested, suggesting the tissue specificity of affinity.

Aminopyridines↗
PubMed1984

Species differences in pulmonary N-oxidation of chlorpromazine and imipramine.

Our previous studies have demonstrated that chlorpromazine (CPZ) and imipramine (IMP) are metabolized appreciably via N-oxidation catalyzed by pulmonary microsomal flavin monooxygenase in the rat but not in the rabbit. The present work deals with the species differences in N-oxidase of pulmonary microsomes from male cat, dog, goat, guinea pig, hamster, mouse, pig, rabbit and rat. Although CPZ-N-oxidizing activities were generally higher than IMP-N-oxidizing activities, the CPZ-/IMP-oxidizing activity ratios were not constant among the species tested. Little or no activity was detected in the guinea pig and rabbit lung. The following ranking was assigned: mouse less than hamster less than pig less than rat less than dog less than cat less than guinea pig less than goat less than rabbit for CPZ, and pig less than rat less than mouse less than dog less than hamster less than cat less than guinea pig less than goat less than rabbit for IMP. Nitrosobenzene, a known inhibitor of N-oxidase reductase, inhibited rather than increasing the N-oxidation of both substrates. Therefore, it is unlikely that the marked species differences in pulmonary N-oxidase activities are due to differences in N-oxide reductase. Optimum pH for CPZ-N-oxidase was relatively broad over a range of 7.4-8.5 for rat and 8-9.5 for other species. The pH optima for IMP-N-oxidase ranged from 8.5 to 9.5. n-Octylamine accelerated CPZ-N-oxidation in most species. IMP-N-oxidation was affected to a lesser extent by this primary amine. DPEA (2,4-dichloro-6-phenyl- phenoxyethylamine ) also stimulated the CPZ-N-oxidation in rat, pig and cat but inhibited IMP-N-oxidation in these species.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗