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S Gasa

Publications and source records attributed to S Gasa.

108 records · Page 6Linked to original sources
PubMed1983

Phosphorylation on protein and carbohydrate moieties of a lysosomal arylsulfatase B variant in human lung cancer transplanted into athymic mice.

Human lung cancer transplanted into athymic mice contains predominantly an acidic variant (designated B1) of lysosomal arylsulfatase B. B1 enzyme was suggested to be phosphorylated and sialylated (Gasa, S., Makita, A., Kameya, T., Kodama, T., Koide, T., Tsumuraya, M., and Komai, T. (1981) Eur. J. Biochem. 116, 497-503). In order to determine the localization of phosphate in B1 enzyme, we labeled in vivo the transplanted tumor with [32P]H3PO4 or [3H]glucosamine and purified B1 enzyme by immunoprecipitation. Bio-Gel chromatography of the labeled B1 enzyme treated with endoglycosidase H demonstrated that both the excluded and included materials were labeled with 32P and 3H. From acid hydrolysate of the excluded materials, phosphorylated serine and threonine were detected. Protein phosphorylation of arylsulfatase was confirmed by in vitro labeling experiments with [gamma-32P]ATP. By incubation of the tumor homogenate with ATP followed by isolation of the enzymes, B1 enzyme had a significant amount of radioactivity, whereas the B enzyme had little; by exogenous protein kinase, partially purified B enzyme was phosphorylated 35 times more than B1 enzyme. Acid hydrolysate of the included materials in the Bio-Gel column demonstrated mannose 6-phosphate and an unknown phosphorylated compound which migrates more than Man-6-P on electrophoresis and chromatography.

Amino Acids↗
PubMed1983

Further study of the chemical structure of the equine erythrocyte hematoside containing O-acetyl ester.

The chemical structure of an equine hematoside, which contained an ester group and comprised 72% of the total erythrocyte gangliosides, was determined by means of nondestructive and destructive procedures. A 400-MHz nuclear magnetic resonance spectrum of the ganglioside in perdeuterodimethyl sulfoxide demonstrated three protons due to a methyl group of an acetyl moiety, as well as amide and anomeric protons which were compatible with those of the ordinary hematoside. The spin decoupling difference spectroscopy of the ganglioside revealed the presence of the following structures. [formula: see text]. A mass spectrum obtained by direct probe analysis of the permethylated ganglioside demonstrated the presence of an O-acetyl-N-glycolylneuraminic acid moiety (m/z 434). Gas chromatography-mass spectrometric analysis of the sialic acid, derivatives from the periodate-oxidized ganglioside, and derivatives from acetalized ganglioside prepared under controlled conditions indicated that the sialic acid of the ganglioside was 4-O-acetyl-N-glycolylneuraminic acid. Thus, the structure of the equine ganglioside was determined as 4-O-acetyl-N-glycolylneuraminyl alpha 2-3 galactosyl beta 1-4 glucosyl beta 1-ceramide. The antigenic properties of this ganglioside were examined. In contrast to ordinary hematoside, which reacted strongly with Hanganutziu-Deicher (H-D) antibodies of a heterophile type in human, this ganglioside did not exhibit any H-D antigenicity. Therefore, a free hydroxy group at C-4 of the N-glycolylneuraminyl moiety in gangliosides appears to be absolutely required for the manifestation of H-D antigenicity.

Animals↗
PubMed1983

Lysosomal arylsulfatases of human leukocytes: increment of phosphorylated B variants in chronic myelogenous leukemia.

Lysosomal arylsulfatases A and B of peripheral leukocytes from patients with chronic myelogenous leukemia and from healthy subjects were studied. Two enzyme activities of leukemia cells were significantly higher than those of cells from healthy subjects, irrespective of total and differential counts of leukemic cells. Upon anion-exchange chromatography, the arylsulfatases of chronic myelogenous leukemia cells and normal leukocytes were separated into the basic B enzyme and its anionic variant (B1) and A enzyme. However, the amount of B1 enzyme relative to B enzyme or the activity ratio of B1 enzyme to total arylsulfatase B (B + B1) was higher in chronic myelogenous leukemia cells than in normal cells. The anionic property of the enzyme was found to be due to phosphate groups bound to the carbohydrate moiety of the arylsulfatase, based on the following results. When B1 enzyme was treated with alkaline phosphatase followed by isoelectric focusing, it was changed to a less anionic enzyme with heterogeneous components which are ascribed to phosphodiester groups linked to the heterogeneous carbohydrate moiety of the enzyme; no effect was observed by sialidase treatment. Upon treatment of B1 enzyme with endo-beta-N-acetylglucosaminidase H, which cleaves sugar chains of a high mannose type in glycoproteins, the anionic heterogeneous components were converted to the basic component similar to B enzyme. From our present and previous observations, it can be concluded that the increase of phosphorylated forms of the lysosomal hydrolase represents one characteristic of rapidly proliferating neoplastic cells.

Cerebroside-Sulfatase↗
PubMed1983

Proton nuclear magnetic resonance of neutral and acidic glycosphingolipids.

A number of intact neutral glycosphingolipids (globo, asialoganglio, neolacto, and gala series), gangliosides, and sulfatide were analyzed by proton nuclear magnetic resonance (NMR) using dimethyl-d6 sulfoxide as a solvent at different conditions of measurement. The chemical shifts of amide proton of ceramide, N-acetylhexosamine and sialic acid moieties were positioned with regularity, thus providing their molar composition. The chemical shifts of amide proton in ceramide moiety differed with respect to constituent fatty acids; delta 7.45 to 7.52 ppm at 25 degrees C for the nonhydroxy acids and 7.32 to 7.42 ppm for the hydroxy acids. The chemical shifts of methyl proton in N-acetyl group were distinguished between N-acetylhexosamine and N-acetylneuraminic acid, and those in N-acetylgalactosamine were discriminated between neutral glycolipids and gangliosides. In the presence or absence of D2O in dimethyl sulfoxide at 110 degrees C, the anomeric protons resonated with regularity characteristic of respective monosaccharide linkages, and the anomeric protons of N-acetylgalactosamine in neutral glycolipids and gangliosides were clearly distinguished. The present study thus demonstrates the general applicability of NMR procedure to glycosphingolipids, providing the determination of chemical composition of both the lipophilic and carbohydrate moieties and the structural elucidation.

Glycosphingolipids↗
PubMed1982

UDP-N-acetylgalactosamine:globoside alpha-3-N-acetylgalactosaminyltransferase. Purification, characterization, and some properties.

A UDP-N-acetylgalactosamine:globoside alpha-3-N-acetylgalactosaminyltransferase has been purified over 3500-fold in 4% yield from a Triton X-100 extract of canine spleen microsomes by affinity chromatography on globoside acid-agarose. Sodium dodecyl sulfate gel electrophoresis of the purified enzyme revealed two major bands with molecular weights of 66,000 and 56,000. Judging from the molecular weight of 120,000 estimated by Sephadex gel filtration in Triton X-100 and the above electrophoretic result, the enzyme presumably exists normally as a dimer. It required Mn2+ for its activity and had a pH optimum at 6.7-6.9. The enzyme catalyzes the transfer of N-acetylgalactosamine in alpha 1 leads to 3 linkage to globoside. Neither Fuc alpha 1 leads to 2Gal beta 1 leads to 4Glc nor H blood group substance nor deglycosylated mucin were acceptors. This indicates that the enzyme was distinct from both the N-acetylgalactosaminyltransferases converting the H to the A blood group substance and catalyzing synthesis of the Ser(Thr)-GalNAc linkage. Studies on substrate specificities indicate that the preferred substrates have the general structure GalNAc beta 1 leads to 3Gal-OR in which the nature of the R moiety has relatively little effect on activity. Kinetic analysis indicates UDP is a competitive inhibitor with respect to UDP-N-acetylgalactosamine and a noncompetitive inhibitor with respect to globoside. These studies demonstrate the first report of the properties of a purified enzyme catalyzing the transfer of sugar residues to glycolipids.

Animals↗
PubMed1982

Blood-group A and the related glycolipids of human lung.

Three glucosamine-containing sphingoglycolipids were isolated from human lung tissue of a blood group-A subject. They were hexaglycosyl, pentaglycosyl, and tetraglycosyl ceramides. The hexaglycosyl ceramide exhibited blood group-A antigenicity, and the following chemical structure was proposed on the basis of sequential glycosidase treatment and methylation analysis. (Formula: see text) The pentaglycosyl ceramide for human lung was a blood group H(O)-active glycolipid having a carbohydrate composition of Fuc : GlcNAc : Gal : Glc (1 : 1 : 2 : 1). The tetraglycosyl ceramide is probably paragloboside (lactoneotetraosyl ceramide).

ABO Blood-Group System↗
PubMed1981

Arylsulfatases of human-lung tumors transplanted into athymic mice. Cancer-associated modification of arylsulfatase B variant.

The activities and properties of arylsulfatase A and B from human lung carcinoma transplanted into athymic mice were demonstrated. The activities of arylsulfatase A and B from transplanted carcinomas with four histological types were more than twofold higher as compared to those from surgical tumors, except for arylsulfatase A activity in blastoma. Arylsulfatase B in transplanted tumors was almost completely replaced, except for blastoma, by an anionic B variant (B1) which was a minor component of arylsulfatase B in surgical lung tumor and absent in normal human lung. The properties of arylsulfatases A and B from transplanted tumors were essentially identical, respectively, with those from normal lung or surgical tumors in respect of molecular weight, heat stability, pH optimum, isoelectric point (pI), Km, time course profile and substrate specificity. Arylsulfatase B1 showed the properties similar to B enzyme except for net charge. The cause of the negative charge of tumor B1 enzyme was investigated. By the action of phosphatase, which was added exogenously or had been persistently included in the partially purified enzyme preparation, B1 enzyme (pI 7.5) shifted to about pI 8.2. Treatment of B1 enzyme with neuraminidase, concomitant with the endogenous phosphatase, resulted in marked increase (pI 9.5) of the isoelectric point, identical to that of arylsulfatase B. Thus, it is most probable that tumor B1 enzyme is modified by additional sialic acid and phosphate bound to arylsulfate B.

Animals↗
PubMed1980

Characterization of gangliosides from equine kidney and spleen.

Gangliosides were isolated from equine kidney and spleen, and their carbohydrate and lipid moieties were characterized. Among the long-chain bases, considerable proportions of trihydroxy bases (42.3 to 61.2% of the total bases), in which phytosphingosine was predominant were found in all the ganglioside classes. The other major base was sphingosine. Among the constituent fatty acids, long-chain acids (with a carbon number of more than 20), comprised approximately half the total acids, with some alpha-hydroxy and mono-unsaturated acids. By means of sequential hydrolysis with glycosidases coupled with methylation analysis, the following kidney and spleen gangliosides were characterized: hematoside containing both N-acetyl and N-glycolylneuraminic acids; ganglioside GM2 having both types off sialic acid; ganglioside GM1 having mainly N-glycolylneuraminic acid (83 to 86%); ganglioside GD1a having mainly N-glycolylneuraminic acid (71 to 95%). Ganglioside GD3 containing almost exclusively N-glycolylneuraminic acid (93%) was found in the kidney, and ganglioside GD1b having both types of sialic acid in the spleen.

Animals↗
PubMed1980

Elevated activities and properties of arylsulfatases A and B and B-variant in human lung tumors.

The activities of arylsulfatases A and B were determined in human primary and secondary tumor tissues (total, 53 cases) of various histological types. Significantly higher activities of these sulfatases were found in almost all the primary lung carcinomas as compared to their corresponding uninvolved tissues. No significant correlation was demonstrated between the enzyme activities and histological figures (stroma amounts, etc.). Lung adenocarcinoma and squamous cell carcinoma showed the presence of an additional arylsulfatase component (B1) which was not detected in normal human lung. The tumor arylsulfatase B1 had an isoelectric point (pI) of 6.7 and was clearly distinguished from arylsulfatase A (pI 4.9) and arylsulfatase B (pI 9.1 to 9.2) in normal lung and lung tumor. The tumor B1 enzyme was demonstrated to be most probably an isoenzyme of arylsulfatase B, since this unusual enzyme was indistinguishable from arylsulfatase B in terms of Ag+ inhibition; its kinetic parameters of Km for p-nitrocatechol sulfate, which was 2.9 mM with B1; optimum pH of 6.3 for B1; heat stability; and substrate specificity for three synthetic and two physiological substrates.

Adenocarcinoma↗
PubMed1979

Glycolipids in human lung carcinoma of histologically different types.

Glycolipids were isolated from primary human lung carcinoma tissue of various histologic types: adenocarcinoma, squamous cell carcinoma, and undifferentiated small cell carcinoma. Each type of carcinoma had a characteristic glycolipid pattern. The major glycolipids isolated were ceramide monohexosides, ceramide dihexosides, ceramide trihexosides, globoside, and hematoside. Squamous cell carcinoma and undifferentiated small cell carcinoma showed marked increases of ceramide monohexosides and dihexosides. Adenocarcinoma had a much higher level of the sulfatide (ceramide 3-sulfate-galactoside) as compared to squamous cell carcinoma, undifferentiated small cell carcinoma, or normal lung tissue. Embryonic tissue had more significant levels of sulfatide than did the other carcinomas. Adenocarcinoma had significantly lower levels of glycolipids due mainly to a decrease in the amount of ceramide monohexosides and dihexosides and hematoside.

Adenocarcinoma↗
PubMed1978

Affinity purification and some properties of nucleoside diphosphatase from rat liver cytosol.

Nucleosidediphosphatase (nucleosidediphosphate phosphohydrolase, EC 3.6.1.6) of rat liver cytosol was purified up to 336--fold by the procedure including affinity chromatographies of concanavalin A- and alanine-Sepharose. The final purified enzyme showed a single protein band upon polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. Its native form was found to be a tetramer with molecular weight of 120 000 which consists of subunit with molecular weight of 30 000. The enzyme was found to be a glycoprotein on the basis of its chromatographic behaviour with concanavalin A-Sepharose and positive staining with periodate-Schiff reaction in polyacrylamide gels. Furthermore, the two molecular forms with isoelectric points of 4.7 and 5.0 were demonstrated by electrofocusing, though they did not show any significant difference with respect to their catalytic properties.

Acid Anhydride Hydrolases↗
PubMedDate not supplied

Mechanism of the immunosuppressive effect in vivo of novel immunosuppressive drug beta-SQAG9, which inhibits the response of the CD62L+ T-cell subset.

INTRODUCTION: We synthesized sulfo-glycolipid, beta-SQAG9 (designate square beta-SQAG9 liposome, because it efficiently forms a liposome structure) that possessed immunosuppressive effects such as inhibition of T-cell responses in human allogeneic MLR and skin allograft survival in rats, and bound to CD62L (L-selectin) in vitro. In this study, we further investigated the immunosuppressive mechanism in vivo by beta-SQAG9 liposome in a skin-allografted rat model. METHODS: ACI rats (RT1(a)) were grafted skin of LEW rats (RT1(1)) treated with PBS or beta-SQAG9 liposome IV once a day for 7 days. Subsequently, we investigated the population of T cells and CD62L(+) T-cell subset in the spleen, axillary lymph nodes (ALNs), and peripheral blood of skin-allografted rats by two-color flow cytometry. RESULTS: Five of 11 (45.5%) rats that were treated with 50 mg/kg beta-SQAG9 liposome showed graft survival and another showed moderate rejection in graft. The CD62L(+) T-cell subset population in ALNs of beta-SQAG9 liposome-treated rats decreased in a dose-dependent manner. No significant difference in the T-cell population was observed between the beta-SQAG9 and control groups. These data suggest that beta-SQAG9 could bind to the CD62L(+) T-cell subset in vivo as well as in vitro and affect T-cell migration, which might lead to T-cell tolerance in vivo.

Animals↗