Toshihisa Sumi
Saga University
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Featured researches published by Toshihisa Sumi.
Fish Physiology and Biochemistry | 2001
Toshihisa Sumi; Yoichiro Hama; Hiroki Nakagawa; Daisuke Maruyama; Makio Asakawa
Skin mucus glycoprotein (RGP) was extracted from the skin mucus of rainbow trout, Salmo gairdneri. Alkaline borohydride treatment of RGP yielded a major oligosaccharide alditol NeuAcα2 to6GalNAc-ol and several minor oligosaccharide alditols. A trisaccharide alditol (OS-I) was purified by Sephadex G-25 gel filtration and high-performance liquid chromatography (HPLC). The amount of OS-I was estimated to be 7% in RGP from the amount of GalNAc-ol. Structural determination of the OS-I was examined. Structure of OS-I was identified to be NeuAcα2 to6 (GalNAcα1 to3) GalNAc-ol by α-N-acetylgalactosaminidase digestion, methylation analysis, and 1H-NMR spectroscopy.
Advances in Experimental Medicine and Biology | 2001
Hiroki Nakagawa; Yoichiro Hama; Toshihisa Sumi; Su-Chen Li; Yu-Teh Li
It has been widely recognized that the mucus coat of fish plays a variety of important physical, chemical, and physiological functions. One of the major constituents of the mucus coat is mucus glycoprotein. We found that sialic acids in the skin mucus of the loach, Misgurnus anguillicaudatus, consisted predominantly of KDN. Subsequently, we isolated KDN-containing glycoprotein from loach skin mucus and characterized its chemical nature and structure. Loach mucus glycoprotein was purified from the Tris-HCl buffer extract of loach skin mucus by DEAE-cellulose chromatography, Nuclease P1 treatment, and Sepharose CL-6B gel filtration. The purified mucus glycoprotein was found to contain 38.5 KDN, 0.5% NeuAc, 25.0% GalNAc, 3.5% Gal, 0.5% GlcNAc and 28% amino acids. Exhaustive Actinase digestion of the glycoprotein yielded a glycopeptide with a higher sugar content and higher Thr and Ser contents. The molecular size of this glycopeptide was approximately 1/12 of the intact glycoprotein. These results suggest that approximately 11 highly glycosylated polypeptide units are linked in tandem through nonglycosylated peptides to form the glycoporotein molecule. The oligosaccharide alditols liberated from the loach mucus glycoprotein by alkaline borohydride treatment were separated by Sephadex G-25 gel filtration and HPLC. The purified sugar chains were analyzed b --> 6GalNAc-ol, KDNalpha2 --> 3(GalNAcbeta1 --> 14)GalNAc-ol, KDNalpha2 --> 6(GalNAcalpha1 --> 3)GalNAc-ol, KDNalpha2 --> 6(Gal3alpha1--> 3)GalNAc-ol, and NeuAcalpha2 --> 6Gal NAc-ol. It is estimated that one loach mucus glycoprotein molecule contains more than 500 KDN-containing sugar chains that are linked to Thr and Ser residues of the protein core through GalNAc.
Bioscience, Biotechnology, and Biochemistry | 2010
Yoichiro Hama; Aya Tsuneoka; Ryoji Morita; Osamu Nomoto; Kenshi Yoshinaga; Hideo Hatate; Toshihisa Sumi; Hiroki Nakagawa
Here we report a simple method for the structural analysis of red algal galactan containing 3,6-anhydrogalactose. Structural heterogeneity in the galactan was demonstrated by this method. For selective hydrolysis of 3,6-anhydrogalactosidic linkages in the galactan, conditions for reductive mild acid hydrolysis were examined by characterizing the resulting oligosaccharide alditols by anhydrous mercaptolysis. Residues other than alditols at the reducing ends, including labile 3,6-anhydrogalactose, were liberated quantitatively as diethyl dithioacetal derivatives, whereas alditols at the reducing ends were not derivatized and were liberated as alditols intact. The liberated sugars were then separated and measured quantitatively by gas-liquid chromatography. Heating of agarose in reductive hydrolysis with 0.3 M trifluoroacetic acid in the presence of an acid-stable reducing agent, 4-methyl morpholine borane, at 80 °C for 90 min and for 90 °C for 45 min was found to be optimum for the selective hydrolysis of 3,6-anhydrogalactosidic bonds, without detectable cleavage of other glycosidic bonds.
Journal of Biological Chemistry | 1994
M. Kimura; Yoichiro Hama; Toshihisa Sumi; M. Asakawa; B. N. N. Rao; A. P. Horne; Su-Chen Li; Yu-Teh Li; Hiroki Nakagawa
Glycobiology | 2007
Hiroki Nakagawa; Yoichiro Hama; Toshihisa Sumi; Su-Chen Li; Karol Maskos; Kittiwan Kalayanamitra; Shuji Mizumoto; Kazuyuki Sugahara; Yu-Teh Li
Analytical Biochemistry | 1998
Yoichiro Hama; Hiroki Nakagawa; Mika Kurosawa; Toshihisa Sumi; Xi Xia; Kuniko Yamaguchi
Bioscience, Biotechnology, and Biochemistry | 1997
Toshihisa Sumi; Yoichiro Hama; Daisuke Maruyama; Makio Asakawa; Hiroki Nakagawa
Fisheries Science | 1997
Toshihisa Sumi; Yoichiro Hama; Daisuke Maruyama; Makio Asakawa; Hiroki Nakagawa
Journal of Fish Biology | 2004
Toshihisa Sumi; Yoichiro Hama; Hiroki Nakagawa; Daisuke Maruyama; Makio Asakawa
Journal of Biochemistry | 1999
Yoichiro Hama; Hiroki Nakagawa; Kiyonori Mochizuki; Toshihisa Sumi; Hideo Hatate