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Biomedical subjects

H Kosugi

Publications and source records attributed to H Kosugi.

44 records · Page 3Linked to original sources
PubMed1984

Effect of malondialdehyde, a product of lipid peroxidation, on the function and stability of hemoglobin.

Malondialdehyde (MDA) was found to react with normal hemoglobin A (Hb A), forming a number of less cationic components which were detected by cellulose acetate electrophoresis and gel electrofocusing. All the modified components moved down the cation-exchange resin at a quicker rate than Hb A, and this chromatographic behavior of the modified components was similar to that of glycosylated Hb A. Some of these modified components were intermolecularly crosslinked, and showed fluorescence with an excitation maximum at 390 nm and an emission maximum at 460 nm. It is likely that MDA reacts nonspecifically with the epsilon-amino groups of lysine and N-terminal amino groups to produce aminoacrolein, crosslinks, and strongly fluorescent 1,4-dihydropyridine-3,5-dicarbaldehyde. Oxygen affinity of the modified hemoglobins was increased. The modified hemoglobins were more readily oxidized into met-form. Mechanical stability of Hb A was also decreased by the modification. These results suggest that a considerable conformational change in Hb A was induced by the treatment with MDA. Since MDA is generated in erythrocytes as a consequence of liquid peroxidation, MDA may react with intracellular Hb A and influence the function and the stability of hemoglobin.

Chromatography↗
PubMed1983

Formation of cross-linked asymmetrical hybrid hemoglobins by double-headed aspirin.

Double-headed aspirin [bis(3,5-dibromosalicyl)fumarate] selectively cross-links hemoglobin molecules between Lys 82 beta 1 and Lys 82 beta 2 and increases solubility of deoxy-Hb S (Walder et al., J. Mol. Biol., 141:195, 1980 and Kikugawa et al., J. Biol. Chem., 257:7525, 1982). We reacted this reagent with the mixture of Hb A and Hb S and the mixture of Hb S and Hb York (beta 146His replaced by Pro). Cross-linked asymmetrical hybrid hemoglobins (alpha 2 beta - beta S and alpha 2 beta Y - beta S) were produced in high yields in addition to the cross-linked parent hemoglobin molecules. Results on electrophoresis, gel electrofocusing, ion exchange column chromatography, mechanical stability and oxygen binding properties showed that the cross-linked asymmetrical hybrid hemoglobins had properties intermediate between those of the cross-linked parent hemoglobins. Oxygen affinities of the cross-linked asymmetrical hybrids were not affected by the addition of 2,3-diphosphoglycerate (DPG) or inositol hexaphosphate, probably due to the presence of a fumaryl group at the DPG binding site.

Aspirin↗
PubMed1983

Characterization and properties of Hb York (beta 146 His leads to Pro).

A second case of Hb York (beta 146 His leads to Pro), was discovered in a patient with polycythemia. The oxygen equilibrium curves (OEC) of red cell suspensions in a buffer (pH 7.4) at 37 degrees C revealed a biphasic curve with a P50 of only 12.5 mm Hg (normal value: 26.5 +/- 1.0 mm Hg). The purified Hb York had an extremely high affinity for oxygen with diminished cooperativity and decreased Bohr effect. The oxygen affinity was significantly reduced by inositol hexaphosphate. Molecular stability studies by mechanical shaking of various liganded forms of Hb York revealed stabilities between those of Hb A and Hb S. Isolated beta Y-subunits were more unstable than beta A-subunits at every pH examined. Hb York was 1.4 times more unstable than Hb A in 18.9% isopropanol.

Chemical Phenomena↗
PubMed1977

The structure of triglyceride in human sebum.

1) A relatively large quantity of branched chain and odd-carbon-number fatty acids were found in human sebum. 2) These acids were present in each lipid fraction (cholesterol ester, triglyceride and free fatty acid) of sebum. 3) In the triglyceride molecule, these acids were found mainly on the 2-position.

Chemical Phenomena↗
PubMed1975

Ribosomal proteins from streptomycin-resistant and dependent mutants, and revertants from streptomycin-dependence to independence in Bacillus subtilis.

Streptomycin-resistant and dependent mutants were isolated from Bacillus subtilis ATCC 6633. Ribosomal proteins were analysed from six such mutants with chromatography on carboxymethyl cellulose or phosphocellulose columns. An altered specific 30s ribosomal protein, 30B, could be detected in all of these mutants. Streptomycin-independent revertants were isolated from a streptomycin-dependent strain. Some of them had an altered 30s ribosomal protein, 30A, and some others had an altered 30C protein. It was shown that from the data of partial N-terminal amino acid sequences together with amino acid compositions and mobilities on two-dimensional gel electrophoresis of these proteins that 30A, 30B, and 30C proteins were homologous with S5, S12 and S4 of E. coli 30s ribosomal proteins, respectively.

Amino Acid Sequence↗