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Y Ishimura

Publications and source records attributed to Y Ishimura.

At least 181 records · Page 10Linked to original sources
PubMed1979

Immunohistochemical localization of adrenodoxin and adrenodoxin reductase in bovine adrenal cortex.

The zonal distribution of adrenodoxin and adrenodoxin reductase (EC 1.6.7.1) in the bovine adrenal cortex as well as their intracellular localization has been studied by the direct method of peroxidase-labelled antibody (Fab' or F(ab')2 fraction) technique. The results indicated that both proteins localized mainly in zonae fasciculata and reticularis whereas very few were present in the zona glomerulosa. Only parenchymal cells in the adrenal cortex were proved to contain both proteins. The intracellular localization of both adrenodoxin and the reductase was demonstrated to be exclusively on the inner membrane of mitochondria of these parenchymal cells by immunoelectron microscopy. The validity of the immunocytochemical method employed in this study to determine the fine localization of both proteins in the mitochondria as well as the significance of the zonal distribution in relation to the function of each individual zone is discussed.

Adrenal Cortex↗
PubMed1978

Magnetic circular dichroism of Pseudomonas putida cytochrome P-450 in near infrared region.

Magnetic circular dichroism spectra of oxidized, reduced and carbonmonoxy reduced forms of cytochrome P-450 from D-camphor grown Pseudomonas putida (P-450cam) were studied in the near infrared region (650 to 1200 nm) at various temperatures in the presence of D-camphor. Oxidized P-450cam with camphor exhibited positive (+) and negative (-) magnetic CD bands at 825 and 970 nm, respectively, and both of them were assigned to Faraday B terms. The magnetic CD spectrum of reduced P-450cam in the presence of D-camphor exhibited at least five components in the region between 650 to 1175 nm and one of them at 760 nm showed considerably smaller magnitude than that of the corresponding band of deoxymyoglobin. These results were interpreted to mean that the heme-iron in both oxidized and reduced P-450cam has a ligand field symmetry lower than C4v, i.e. a strong rhombic character of the heme in cytochrome P-450. Carbonmonoxide complex of reduced P-450cam exhibited no detectable magnitude of magnetic CD in the near infrared region but showed CD bands at 710 (-) and 850 (+) nm. The results were compared and discussed with those of carbonmonoxy hemoglobin and myoglobin. In addition, temperature dependent changes in the spin state of oxidized P-450cam from high to low by decrease of temperature were observed by measuring both magnetic CD and absorption spectra in the near ultraviolet and visible regions (300 to 650 nm), provided that the temperature of the sample was varied slowly (approximately 3 degrees C/min) between room and liquid nitrogen temperature in a 0.03 M phosphate buffer (pH 7.2) containing a saturated amount of D-camphor and 70% (v/v) glycerol. The significance of this phenomenon is also discussed.

Circular Dichroism↗
PubMed1976

Negligible amount of copper in hepatic L-tryptophan 2,3-dioxygenase.

During the purification of L-tryptophan 2,3-dioxygenase, a protohemoprotein from rat liver, both copper and heme contents of the preparations were found to be progressively increased as purification proceeded. However, the greater part of copper was removed in the late stages of the purification giving a copper to heme ratio less than 0.4. The small amounts of copper could further be reduced by one-half, by a mild treatment of enzyme with chelators such as ethylenedi aminetetraacetate, without any accompanying decrease in enzymatic activity. Since the turnover number of these enzyme preparations expressed per mol of enzyme-bound heme, 200 to 277 min-1 at 25 degrees, were either comparable to or slightly higher than those reported with homogeneous enzyme preparations, the heme in the preparation was considered to be of fully active L-tryptophan 2,3-dioxygenase and, therefore, such a small ratio of copper to heme, 0.1 to 0.3, indicated that copper is not a constituent of L-tryptophan 2,3-dioxygenase of rat liver. The findings were thus inconsistent with the results of Brady et al. (Brady, F. O., Monaco, M. E. Forman, H. J. Schutz, G., and Feigelson, P. (1972) J. Biol. Chem. 247, 7915-7922), who found that L-tryptophan 2,3-dioxygenase contained 2 g atoms of copper and 2 mol of heme/mol of enzyme. Possible reasons for this discrepancy have been discussed.

Animals↗
PubMed1976

Binding of nitric oxide to reduced L-tryptophan-2,3-dioxygenase as studied by electron paramagnetic resonance.

Ferrous L-tryptophan-2,3-dioxygenase reacts with nitric oxide both in the presence and in the absence of L-tryptophan. Electron paramagnetic resonance studies suggest that the proximal ligand of the heme is a nitrogen atom, probably from an histidyl residue. The interaction of the protein with substrate changes both the symmetry of the paramagnetic center and the mode of interaction of the iron atom with its two axial ligands, NO and the proximal nitrogen atom. Optical absorption and EPR spectra suggest that the affinity of NO for tryptophan dioxygenase increases in the order: tryptophan dioxygenase, tryptophan dioxygenase + alpha-methyltryptophan, tryptophan diogenase " 5-hydroxytryptophan, tryptophan dioxygenase + L-tryptophan. A possible correlation between the number of superhyperfine lines in the EPR spectrum and the affinity of the enzyme for NO is discussed.

Binding Sites↗
PubMed1976

On the prosthetic groups of L-tryptophan 2,3-dioxygenase from Pseudomonas: evidence for noninvolvement of copper in the reaction.

The amounts of copper present in highly purified preparations of L-tryptophan 2,3-dioxygenase from Pseudomonas fluorescens have been shown to be negligible by six different methods of copper determination. It has also been demonstrated that, during the purification, the heme content of enzyme preparations increased in parallel with the specific enzyme activity, whereas that of copper decreased. These results, together with the finding that the inhibitory effects of copper chelators on the enzyme could be attributable to some other action of these chemicals rather than to their chelating properties, indicate that copper is not an essential component of L-tryptophan 2,3-dioxygenase.

Binding Sites↗
PubMed1975

Effects of gentamicin on the intestinal bacterial flora of rats.

1) Normal intestinal microbial flora (NF) in feces of rats were examined before and after administration of gentamicin (GM). Although GM caused no influence on NF after 6 hours, the number of NF decreased markedly 24 hours after GM, viz., the count of coliforms, enterococci and lactobacilli was reduced to 1/10-1/100 of the control value while proteus and fusobacteria declines in number down to 1/100-1/1,000 times as low as the control value. 2) The decreased count of NF tended to recover to some degree at the end of the 1st therapeutic week and the considerably recovered count continued thereafter indicating about 1/10 times as low as the control value until a 12-week experimental period, except that the count of lactobacilli returned to almost normal. 3) Susceptibility of coliforms isolated from GM-treated rats to GM was nearly equal to that of the bacteria isolated from the untreated control rats, which revealed no development of drug resistance to GM. 4) The increasing rate of body weight was higher in GM-treated rats than in the control, and the feed intake was consequently great in the former.

Animals↗
PubMed1975

Effects of gentamicin on the thyroid function of rats.

The effect of gentamicin (GM) on the thyroid function was investigated in relation with its stimulating action to the growth of rats at a very small dose level. The results may be summarized as follows: (1) Changes in 131-I-uptake of the thyroid after administration of GM were unremarkable. The change in wet weight of the thyroid was also unremarkable. Therefore, GM may not affect the thyroid itself. (2) GM-treated rats clearly showed a decrease in 131-I-triiodothyronine resine sponge uptake (trisorb test) as compared with the control animals, viz.,GM-treated rats indicated hypofunction of the thyroid. (3) Thyroxin (t4) levels in theserum, determined by 125-I-T4 resine sponge uptake (tetrasorb test), were apparentlylower in the GM-treated rats than in the control. (4) The thyroid function test for synthesis of the hormones revealed an increase in diiodotyrosine (DIT) value and decreases in 3, 5, 3'-triiodothyronine (T3) and T4 values in the GM-treated groups as compared with the values in the control. (5) In view of the above results iit was obvious that GM does not cause abnormalities on iodine-uptake, iodine oxidation, organic conversion to iodinated tyrosines, deiodination and thyroglobulin. In contrast, GM may induce abnormality on coupling reaction from DIT to T3 and T4 because the increase in DIT value and decreases in T3 and T4 values are seen following administration of GM. The whole of these facts seems to play an important role in stimulation to growth of rats after administration of the drug.

Adrenal Glands↗