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Biomedical subjects

T Isobe

Publications and source records attributed to T Isobe.

At least 271 records · Page 15Linked to original sources
PubMed1981

The amino-acid sequence of the alpha subunit in bovine brain S-100a protein.

The brain specific S-100 protein is a mixture of two components S-100a and S-100b with a subunit composition alpha beta or beta 2 respectively. The amino acid sequence of the beta subunit has been previously determined. This paper presents the sequence of the alpha subunit in the S-100a protein. The alpha subunit consists of 93 amino-acid residues and has a relative molecular mass of 10,400. The sequence shows extensive homology (58%) with that of the beta-subunit and shares an apparent calcium binding site in the C-terminal half of the molecule, suggesting a close evolutionary relationship between these subunits.

Amino Acid Sequence↗
PubMed1981

Structural relation of two S-100 proteins in bovine brain; subunit composition of S-100a protein.

Dodecyl sulfate/urea/polyacrylamide gel electrophoresis of S-100a protein, one of the two major components of the brain-specific S-100 protein, indicated the presence of two different subunits in the protein. These subunits (alpha and beta subunits) were purified from the aminoethylated protein by column chromatography on Sephadex G-75, and the purified subunits were subjected to analyses. The results have shown that S-100a protein is a dimer of alpha and beta subunits, with each subunit having a molecular weight of approximately 10500. Structural comparison of these subunits with the subunit of S-100b protein, the other component of S-100 protein consisting of two identical subunits with known amino acid sequence, has revealed that the beta subunit and the subunit of S-100b protein are identical, so that S-100a protein is related to S-100b protein by sharing one of the subunits as a common structural constituent.

Amino Acids↗
PubMed1981

Localization of the carbohydrate units in a human immunoglobulin light chain, protein Sm lambda.

The carbohydrate structure and complete amino acid sequence of a human lambda-type immunoglobulin light chain, protein Sm lambda has been determined. The protein was isolated from the urine of a patient with a plasma cell dyscrasia resembling gamma-heavy-chain disease. 13 tryptic peptides covering the entire polypeptide chain of 135 residues were isolated from the aminoethylated protein, and 15 chymotryptic peptides, accounting for 131 residues, were recovered from the carboxymethylated protein. The sequence of 18 of these peptides was partially or completely determined by the Edman-dansyl technique or C-terminal analysis, permitting the establishment of the complete primary structure of the polypeptide chain. The sequences established that this light chain possessed an intramolecular deletion of 81 amino acid residues. The N-terminal 30 residues showed considerable homology with other lambda chains of subgroup II. The defect began at position 31, in the first hypervariable region, and encompassed the remainder of the variable region through position 109. The constant region was fully intact and normal synthesis recommenced with a glutaminyl residue at position 110, the first residue of the constant region. This light chain contained carbohydrate in the hypervariable region just preceding the deletion. The precise number and locations of the oligosaccharide chains were established by amino acid sequence analysis of glycopeptides isolated from proteolytic hydrolysates by chromatography on Bio-Gel P-6 columns. These studies showed that protein Sm lambda contains one N-glycosidically-linked chain attached to asparagine-25 and one O-glycosidically-linked oligosaccharide chain attached to serine-21. The structures of the oligosaccharide chains were determined by methylation analysis, gas chromatography and hydrolysis with specific glycosidases. The structure of the N-glycosidically-linked chain was NeuAc(alpha 2 leads to 6)Gal(beta 1 leads to 4)GlcNAc(beta 1 leads to 2)Man(alpha 1 leads to 6)[NeuAc(alpha 2 leads to 6)Gal(beta 1 leads to 4)GlcNAc(beta 1 leads to 2)Man(alpha 1 leads to 3)]Man(beta 1 leads to 4)GlcNAc(beta 1 leads to 4)[Fuc alpha 1 leads to 6]GlcNAc leads to Asn. The second O-glycosidically-linked chain was a disialylated tetrasaccharide with the structure, Neu(alpha 2 leads to 3)Gal(beta 1 leads to 3)[NeuAc(alpha 2 leads to 6)GalNAc leads to Ser. This mucin-type disialylated tetrasaccharide in close proximity to N-asparagine-linked chains has not been previously observed in the oligosaccharide chains of immunoglobulins.

Amino Acid Sequence↗
PubMed1981

The amino acid sequence of the tryptophan-containing subunit (alpha-subunit) of bovine brain S-100 protein.

The tryptophan-containing subunit (alpha-subunit) of bovine brain S-100 protein was purified from a S-aminoethyl derivative of S-100a protein, and its amino acid sequence was determined. The alpha-subunit contained 93 residues, including one tryptophan, and had a molecular weight of 10,400. The sequence shows an extensive homology (58% identity) to the sequence of another "tryptophan-free" subunit (beta-subunit) found in both S-100a and S-100b protein, and has a calcium binding site characteristic of the "E-F hand" proteins, such as calmodulin or troponin C. The tryptophan residue is located at position 90 which is presumably adjacent to the C-terminal end of the alpha-helix following the calcium binding loop, and thus appears likely to serve as a specific probe in structure-function studies of S-100 protein.

Amino Acid Sequence↗
PubMed1981

Juvenile rheumatoid arthritis with IgA deficiency and appearance with febrile episode.

A 24-year-old female had juvenile rheumatoid arthritis since the age of 3, with systemic manifestations such as fever, polyarthralgia, micrognathia, splenomegaly, hepatomegaly, lymphadenopathy, subcutaneous nodules, hidden rheumatoid factor of IgG type. Particularly noteworthy is selective IgA deficiency in this patient, with increases in concentration up to 50 mg/dl in the serum concurrently with the repeated febrile attacks in the clinical course.

Adult↗
PubMed1980

A new acidic protein in porcine brain.

An extremely acidic protein has been isolated in a purified form from porcine rain extract, by (NH4)2SO4 fractionation followed by column chromatography on DEAE-Sephadex A-50 and on Sephadex G-75. The purified protein was tentatively named as glutamic acid-rich protein because it was characterized by its remarkably high content of glutamic acid which accounted for 49% of the total amino acid composition. The protein appeared to be a single polypeptide chain with a molecular weight of 56 000-58 000, and had an isoelectric point of 4.6. The N-terminal amino acid sequence was Asp-Glu-Pro-Pro-Ser-Glu-Gly. The immunochemical analysis using rabbit antiserum prepared to the porcine protein has suggested that it is present in the brain of human, cow, cat, dog and goat as well as in various goat organs including liver, kidney, heart, small intestine and spleen.

Amino Acids↗