Jun Sugihara
Kyushu University
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Publication
Featured researches published by Jun Sugihara.
Journal of Clinical Investigation | 1985
Jun Sugihara; Takashi Imamura; Seiho Nagafuchi; Joseph Bonaventura; Celia Bonaventura; Robert Cashon
We encountered an abnormal hemoglobin (Rahere), with a threonine residue replacing the beta 82 (EF6) lysine residue at the binding site of 2,3-diphosphoglycerate, which was responsible for overt erythrocytosis in two individuals of a Japanese family. Hemoglobin Rahere shows a lower oxygen affinity on the binding of 2,3-diphosphoglycerate or chloride ions than hemoglobin A. Although a decrease in the positive charge density at the binding sites of 2,3-diphosphoglycerate in hemoglobin Rahere apparently shifts the allosteric equilibrium toward the low affinity state, it greatly diminishes the cofactor effects by anions. The oxygen affinity of the patients erythrocytes is substantially lowered by the presence of bezafibrate, which combines with sites different from those of 2,3-diphosphoglycerate in either hemoglobin Rahere or hemoglobin A.
Biochimica et Biophysica Acta | 1981
Jun Sugihara; Takashi Imamura; Taiji Imoto; Toshiyuki Yanase
Abstract High-performance liquid chromatography on a reversed-phase column was applied to the structural study of the rare hemoglobin variant found in a Japanese family, which was then identified as Hb New York [113(G15) β valine → glutamic acid]. A reduced oxygen affinity is associated with this amino acid substitution, the difference in log P 50 being 0.1 at pH 7.46. The substitution of a glutamyl residue for valine may destabilize the α 1 β 1 contacts in the oxyhemoglobin structure, shifting the allosteric equilibrium towards the T form.
Hemoglobin | 1984
Jun Sugihara; Eisuke Yokota; Masaaki Kagimoto; Yasushi Naito; Takashi Imamura
Hemoglobin G Waimanalo, in which an asparagine residue is substituted for an aspartic acid at position 64 (E13) of the a-chains, was found in a Japanese family. The propositus was a 40-year-old man with normal hematological parameters. Electro-phoresis of the hemolysates on a cellulose acetate sheet detected a hemoglobin variant that migrated slower than Hb A. The relative mobility was -4.88 at pH 8.6 (1). The variant, Hb A2, and Hb F comprised 24.1%, 2.0%, and 1% of the total hemoglobins, respectively (2).
Biochimica et Biophysica Acta | 1982
Jun Sugihara; Takashi Imamura; Hidenori Yamada; Taiji Imoto; Toshikazu Matsuo; Ikuo Sumida; Toshiyuki Yanase
Hemoglobin Ogi, in which an arginine is substituted for a leucine residue at position 34 of the alpha-chain, was detected in a Japanese family. Although slightly increased oxygen affinity is associated with this amino acid substitution in the alpha 1 beta 1 contact, it is without obvious deleterious effect on the hematological parameters of the individuals heterozygous for this variant.
Biochimica et Biophysica Acta | 1983
Jun Sugihara; Takashi Imamura; Masaaki Kagimoto; Toshikazu Matsuo; Hidenori Yamada; Taiji Imoto; Toshiyuki Yanase
Abstract Hemoglobin Munakata, in which a methionine residue is substituted for a lysine residue at position FG2(90) of the α-chain, was detected in a Japanese family. Slightly increased oxygen affinity is associated with this amino acid substitution at the α 1 β 2 contact site in the FG nonhelical segment of the α-chain.
Journal of Chromatography B: Biomedical Sciences and Applications | 1984
Takashi Imamura; Jun Sugihara; Eisuke Yokota; Masaaki Kagimoto; Yasushi Naito; Toshiyuki Yanase
Journal of Chromatography B: Biomedical Sciences and Applications | 1982
Jun Sugihara; Takashi Imamura; Toshiyuki Yanase; Hidenori Yamada; Taiji Imoto
Japanese Journal of Medicine | 1989
Masafumi Shirahama; Shizuko Tegoshi; Jun Sugihara; Kohei Nagasawa; Yoshiyuki Niho
Hemoglobin | 1984
Eisuke Yokota; Jun Sugihara; M. Kagimotc; Yasushi Naito; Toshikazu Matsuo; Takashi Imamura
Hemoglobin | 1983
Jun Sugihara; Hitoshi Nakashima; Eisuke Yokota; Masaaki Kagimoto; Takashi Imamura; Hidenori Yamada; Taiji Imoto