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Biomedical subjects

T Yagi

Publications and source records attributed to T Yagi.

At least 685 records · Page 38Linked to original sources
PubMed1980

L-Lysine: 2-oxoglutarate 6-aminotransferase. Subunit structure composed of non-identical polypeptides and pyridoxal 5'-phosphate-binding subunit.

L-Lysine:2-oxoglutarate 6-aminotransferase from Flavobacterium lutescence (= Achromobacter liquidum) has been shown to be composed of one each of four non-identical subunits, A, B1, B2, and C. The subunits were isolated by gel filtration, and DEAE-cellulose chromatography in the presence of 8 M urea. Their molecular weights were determined by ultracentrifugation, gel electrophoresis and gel filtration: subunit A 24,000; B1 28,000; B2 28,000; C 45,000. These subunits were all different in amino acid composition. Of the two molecules of bound pyridoxal 5'-phosphate, the one which absorbs at 415 nm is bound to subunit B2 and participates in the catalytic action of the enzyme.

Amino Acids↗
PubMed1980

Amino acid sequence of cytochrome c3 from Desulfovibrio vulgaris, Miyazaki.

The complete amino acid sequence of a tetrahemoprotein, cytochrome c3 isolated from Desulfovibrio vulgaris, Miyazaki, was determined to be Ala-Pro-Lys-Ala-Pro-Ala-Asp-Gly-Leu-Lys-Met-Asp-Lys-Thr-Lys-Gln-Pro-Val-Val-Phe -Asn-His-Ser-Thr-His-Lys-Ala-Val-Lys-Cys-Gly-Asp-Cys-His-His-Pro-Val-Asn-Gly-Lys-Glu-Asn-Tyr-Gln-Lys-Cys-Ala-Thr-Ala-Gly-Cys-His-Asp-Asn-Met-Asp-Lys-Lys-Asp-Lys-Ser-Ala-Lys-Gly-Tyr-Tyr-His-Ala-Met-His-Asp-Lys-Gly-Thr-Lys-Phe-Lys-Ser-Cys-Val-Gly-Cys-His-Leu-Glu-Thr-Ala-Gly-Ala-Asp-Ala-Ala-Lys-Lys-Lys-Glu-Leu-Thr-Gly-Cys-Lys-Gly-Ser-Lys-Cys-His-Ser. The highest homology was found between the sequence of cytochrome c3 of D. vulgaris, Miyazaki, and that of D. vulgaris, Hildenborough, on comparison among various cytochrome c3'S. These two consist of 107 amino acid residues and they differ by 14 residues.

Amino Acid Sequence↗
PubMed1980

Effect of digitonin on photophosphorylation and light-induced H+ uptake in isolated spinach chloroplasts.

The effects of the presence of digitonin in the reaction mixture on photophosphorylation, light-induced H+ uptake, and the size of isolated spinach chloroplasts were studied. Digitonin inactivated photosystem II and dissipated light-induced pH increase without affecting the photophosphorylation driven by photosystem I. Digitonin increased the concentration of NH4Cl required for uncoupling. This effect of digitonin was diminished by valinomycin which barely affects phosphorylation by itself. Although such properties have all been observed with digitonin subchloroplast particles, digitonin at the concentration required for acquiring such properties had little effect on the size of chloroplasts. These results suggest that the characteristic effects of digitonin subchloroplast particles are caused by thylakoid membranes penetrated by digitonin but not by the size of membrane vesicles. Both in chloroplasts with digitonin in the reaction mixture and in digitonin subchloroplast particles, N,N'-dicyclohexylcarbodiimide, purine nucleoside di- and tri-phosphates, and organic bases with low pKa values (pyridine and aniline) made the light-induced pH increase detectable, and this was lost upon the addition of proton ionophores. These results suggest that the lack of the light-induced pH increase by chloroplasts with digitonin in the reaction mixture and by digitonin subchloroplast particles is caused both by a membrane leaky to protons and by the loss of internal buffering capacity of thylakoids. Furthermore, the phosphorylation of chloroplasts with digitonin in the reaction mixture and of digitonin subchloroplast particles is considered to be driven by the proton motive force as is that of chloroplasts without digitonin.

Chloroplasts↗
PubMed1980

Bloom's syndrome in a Japanese girl.

Clinical, cytogenetic, and immunological data of a 5-year-old Japanese girl with Bloom's syndrome are described. Growth deficiency, photosensitivity, and a very mild facial telangiectatic erythema were present. Cytological studies revealed chromosomal aberrations and the characteristic high frequency in sister chromatid exchanges. Immunological studies showed that the serum levels of IgM and IgA, but not IgG, were abnormally low as compared to the age-matched control values and that the generation of cytoplasmic immunoglobulin-producing cells in the peripheral blood lymphocytes, which was evaluated in the in vitro pokeweed mitogen-stimulated cultures, was markedly reduced.

Abnormalities, Multiple↗
PubMed1980

A study of the mineral phase of pulp calcification.

Physico-chemical properties of pulp calcification were studied by means of X-ray microbeam diffraction, electron spin resonance (ESR), X-ray energy-dispersive analysis, and chemical analysis. The material was obtained from the second molar of the right mandible of a 25-year-old woman. X-ray diffraction and ESR analyses showed that calcium salts of the calcification are deposited in the form of apatitie, possibly carbonate-containing apatite. Furthermore, the mineral phase of the calcification was found to be similar to that of bone rather than that of dentin with regard to crystallinity and inorganic content. An unexpected finding was that high concentrations of iron were detected in some areas near the surface of the calcification. The question remains open as to what role, if any, iron may play in the formation of pulp calcification.

Adult↗
PubMed1980

Correlated microradiography, X-ray microbeam diffraction and electron probe microanalysis of calcifications in an odontoma.

Using microradiography, X-ray microbeam diffraction and electron probe microanalysis, a correlated morphologic crystallographic study was performed on dysplastic enamel in a compound odontoma. The tumor was found in the lateral incisor-canine region of the left mandible of a 36-year-old woman. A conspicuous feature was the presence of hypomineralized areas, which were situated in the proximity of enamel surface and distinctly demarcated from the adjacent enamel. X-ray microbeam diffraction and electron probe microanalysis showed that these lesions have a lower crystallinity and a higher concentration of magnesium as compared with the adjacent enamel. In addition, the present study revealed the presence of two other types of calcifications: (1) calcified structures within the fissure or on the enamel surface, which include lacunae of varying size and which resemble a form of coronal cementum, and (2) spherical calcifications which may be an epithelial product.

Adult↗
PubMed1980

Application of Mössbauer spectroscopy to wet bacterial cells.

Although Mössbauer spectroscopy has been applied only to samples in the dry or frozen state, we present evidence showing that this spectroscopy is applicable to biological iron compounds in the wet state if they are tightly bound to the cell membrane or cell wall.

Cell Membrane↗
PubMed1979

Purification and properties of cytochrome c-553, an electron acceptor for formate dehydrogenase of Desulfovibrio vulgaris, Miyazaki.

Cytochrome c-553 of Desulfovibrio vulgaris, Miyazaki, was purified to homogeneity. The absorption spectrum of the ferro form has four peaks at 553, 525, 417 and 317 nm with a plateau near 280 nm, and that of the ferri form has three peaks at 525, 410 and 360 nm with a plateau near 280 nm and a shoulder at 560 nm. The millimolar absorbance coefficient of the alpha-peak of the ferro form is 23.9. The molecular weight of cytochrome c-553 is 8000, and it contains one heme. Its isoelectric point is rather alkaline, and its standard redox potential is -0.26 V at pH 7.0. Its amino acid composition is unique; it lacks proline, isoleucine and tryptophan. Ferrocytochrome c-553 does not combine with CO, nor does it transfer electrons directly to various redox carriers such as flavin nucleotides, methylene blue, indigodisulfonate, 5-methylphenazinium methyl sulfate, 1-methoxy-5-methylphenazinium methyl sulfate, viologens and cytochrome c3, but is oxidized by ferricyanide or by O2. Cytochrome c-553 can be reduced by formate dehydrogenase of this bacterium in the presence of formate, but not by hydrogenase under H2. The formate dehydrogenase does not reduce cytochrome c3 in the presence of formate. The systematic name for formate dehydrogenase of D. vulgaris is, therefore, established as formate:ferricytochrome c-553 oxidoreductase in EC subclass 1.22.-.

Aldehyde Oxidoreductases↗