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Biomedical subjects

S Gasa

Publications and source records attributed to S Gasa.

At least 73 records · Page 4Linked to original sources

Increased N-acetylglucosamine-1-phosphotransferase activity in sera from patients with leukemia.

In human cancer, lysosomal hydrolases contain increased amounts of phosphorylated sugar chains. Sugar chains of the hydrolases undergo post-translational processing which is catalyzed by N-acetylglucosamine-1-phosphotransferase (GlcNAc-phosphotransferase) at the first step. In the present study we estimated serum GlcNAc-phosphotransferase in 50 adults suffering from leukemia and myelodysplastic syndrome. The serum GlcNAc-phosphotransferase was increased to moderate or high levels in patients with acute nonlymphocytic leukemia (ANLL), acute lymphoblastic leukemia and chronic myelogenous leukemia, suggesting that the serum transferase is released from leukemic cells. In many cases of ANLL examined, activity of the transferase was decreased concomitantly with reduction of peripheral blastic cells by effective chemotherapy.

Acetyltransferases↗

Human seminal plasma Zn-alpha 2-glycoprotein: its purification and properties as compared with human plasma Zn-alpha 2-glycoprotein.

On the basis of the datum that the level of Zn-alpha 2-glycoprotein (Zn alpha 2gp) in human seminal plasma was about 6-times higher than that in adult serum, Zn alpha 2gp was purified from fresh human seminal plasma approx. 70-fold with 60% yield over seminal plasma by DEAE-Sephacel, Zn-chelate Sepharose 4B and DEAE-5PW column chromatographies. The molecular weight of seminal plasma Zn alpha 2gp was 50,000 on Superose column chromatography, and 40,500 and 41,500 on SDS-polyacrylamide gel electrophoresis in the absence and presence of beta-mercaptoethanol, respectively. Plasma Zn alpha 2gp is a glycoprotein, while the protein from seminal plasma does not contain carbohydrate. The amino acid sequence of the first 17 residues of seminal plasma Zn alpha 2gp was Glu-Asn-Gln-Asp-Gly-Asn-Tyr-Ser-Leu-Thr-Tyr-Ile-Tyr-Thr-Gly-Leu-Ser. This sequence was completely identical with the amino acid residues from Glu-2 to Ser-18 in the N-terminal amino acid sequence of plasma Zn alpha 2gp. These data suggest that both Zn alpha 2gps in plasma and seminal plasma may be expressed from one gene, but their posttranslational modifications are different.

Adult↗

Presence and characterization of glycolipid sulfotransferase in human cancer serum.

Sulfotransferase, which catalyzes sulfation of the carbohydrate of galactosylceramide (GalCer) and is localised in the Golgi membrane of cells, was assayed for activity in human serum. To do this, an organic solvent was added to the incubated reaction mixture containing GalCer as an acceptor and phosphoadenosine phospho[35S]-sulfate as a donor of sulfate to dissociate the synthesized sulfolipid from serum protein. This was followed by isolation of the sulfolipid on an anion-exchange column. Through this procedure, human serum was found to contain sulfotransferase activity. The serum enzyme was activated by Mn2+. Km values of the enzyme for GalCer and 'active sulfate' were 4.6 microM and 5.2 microM, respectively. The enzyme activity was assayed in sera of cancer patients. The serum activity (mean +/- SE, 0.27 +/- 0.027 pmol.microliter-1.h-1) in renal cell carcinoma patients, whose activity has been demonstrated to be elevated, was significantly (P less than 0.005) increased compared to that of the normal control (mean +/- SE, 0.18 +/- 0.0014 pmol.microliter-1.h-1) and of other urological tumors examined.

Biomarkers, Tumor↗

Human blood group A and H glycolipids in porcine plasma. Evidence for acquisition of the erythrocyte antigens from plasma.

Human blood group A- and H-antigenic glycosphingolipids were isolated from pooled porcine plasma. The structures of the A-active hexa- and H-active pentaglycosylceramides of lactoseries (type 1 sugar chain) were the same as those in porcine erythrocytes. These results endorse biochemically the previous observations that the A and H antigens on porcine erythrocytes are taken up from plasma.

ABO Blood-Group System↗

Structural studies of rat cathepsin E: amino-terminal structure and carbohydrate units of mature enzyme.

The amino-terminal structure of rat gastric cathepsin E was identified and compared with the corresponding regions of human procathepsin E and other aspartic proteinases. The alignment revealed that cathepsin E has the most extended amino-terminal structure in aspartic proteinases, thus suggesting that the activation peptide (propeptide) of the human enzyme is 39-residues long. Analysis of oligosaccharide units suggested that rat cathepsin E possesses one N-linked carbohydrate unit, probably of the high mannose type. No evidence was obtained for the presence of O-linked sugars in rat cathepsin E.

Amino Acid Sequence↗

Effects of exercise stress and cold stress on glutathione and gamma-glutamyltransferase in rat liver.

Effects of acute and chronic stress (exercise and cold) on glutathione and gamma-glutamyltransferase (gamma GT) in the rat liver were investigated. Such stress, except for in the case of acute exercise, had no definite influence on the glutathione level. On the other hand, gamma GT activity in both the extramicrosomal and microsomal fractions varied substantially, suggesting that acute exercise increases the release ability of the microsomal membrane of the rat liver, and that swimming training and long-term cold exposure stabilize the membrane. Immunoreactive gamma GT, however, did not always correlate with the enzyme activity, especially in the extramicrosomal fraction. Cross-adaptation appeared to exist between swimming training and chronic cold exposure.

Animals↗

Human blood group glycosphingolipids of porcine erythrocytes.

Two glycosphingolipids with human blood group A and H antigenicity were isolated from porcine erythrocyte membranes which were obtained from the pooled blood. The yield of the A- and H-antigenic glycolipids was approximately 0.2 and 0.1% of total neutral glycolipids, respectively. No B antigen was detected. Through several methods the porcine erythrocyte antigens were all found to belong to lactoseries (type 1 chain), IV2Fuc alpha, IV3GalNAc alpha Lc4Cer for type A and IV2-Fuc alpha Lc4Cer for type H, in contrast to the antigenic glycolipids in human erythrocytes, which mostly belong to neolactoseries (type 2 chain). The constituent fatty acids of the A antigen were 75% normal acids and 25% 2-hydroxy acids, and the long chain base was 95% sphingenine. This is the first demonstration of the A- and H-antigenic glycolipids on erythrocytes of pig in whose gastric mucin the human blood group A and H substances have been demonstrated.

ABO Blood-Group System↗

Glycosphingolipids of porcine blood: human blood group A and H antigens with type 1 chain in erythrocytes and plasma.

Glycosphingolipids were purified from porcine erythrocytes and plasma. Two minor glycolipids with human blood group A and H antigenicities were found in both sources as components. The two antigenic glycolipids were identified as a hexaglycosylceramide (IV3 alpha GalNAc,IV2 alpha Fuc-Lc4Cer) for the A antigen and pentaglycosylceramide (IV2 alpha Fuc-Lc4Cer) for the H antigen and belonged to lactoseries (type 1 sugar chain) in contrast to those with neolacto core (type 2 sugar chain) in human erythrocytes, thereby endorsing biochemically the previous serological observations that the A antigen on porcine erythrocytes is uptake from plasma, probably the H antigen being the case. In addition to major glycolipids of globoseries in red cells and plasma, a variety of acidic glycolipids including two classes of sulphatides (sulphated galactosylceramide and sulphated lactosylceramide) and five classes of gangliosides (GM3, GD3, GM1, fucosyl GM1 and GD1a) containing N-acetylneuraminic acid and N-glycolylneuraminic acid were obtained from plasma.

Animals↗

Training effects on blood zinc levels in humans.

Effects of physical training on fasting erythrocyte and plasma zinc distributions were studied on seven previously sedentary male students. The training consisted of running over 5 km, 6 times/week for 10 weeks. Maximum aerobic capacity (VO2max) and 12 min walk-run performance increased significantly (p less than 0.01) after training. The erythrocyte concentrations of total zinc and of zinc derived from carbonic anhydrase I (CA-I) rose significantly (p less than 0.05) after training, whereas no such effects were noted in CA-II-derived zinc, Cu2Zn2 superoxide dismutase-derived zinc, and other zinc. On the other hand, no effect of training was found in total or alpha 2-macroglobulin-bound zinc in plasma, although albumin-bound zinc concentration declined significantly (p less than 0.05). Following the training period, however, the response to a VO2max test of the van Beaumont quotient (J Appl Physiol 1973;34:102-6) for total plasma zinc had decreased significantly (p less than 0.05), suggesting a relative reduction of the circulating exchangeable zinc. In addition, there were significant (p less than 0.05) decreases in plasma iron and ferritin concentrations after training, indicating latent iron deficiency anemia. These results may suggest that the changes in CA-I-derived zinc and/or albumin-bound zinc portend zinc deficiency during running training and that sports anemia precedes hypozincemia in athletes.

Adolescent↗

Purification and characterization of glutathione disulfide-stimulated Mg2+-ATPase from human erythrocytes.

We have previously shown the presence of two different forms of glutathione disulfide (GSSG)-stimulated Mg2+-ATPases in human erythrocytes. We have now investigated a low-Km form of the enzyme from human erythrocytes. Purification of the enzyme was performed to apparent homogeneity involving procedures of affinity chromatography and gel filtration. The enzyme was composed of two non-identical subunits of Mr = 82K and 62K. The enzyme reconstituted into phospholipid vesicles showed both GSSG-stimulated Mg2+-ATPase activity (285 nmol Pi released/mg protein/min) and active GSSG transport activity (320 nmol GSSG/mg protein/min). The amino acid composition of the enzyme was similar to that of the enzyme purified from cytoplasmic membranes of human hepatocytes. These enzymes were immunologically cross reactive. These results indicate that this enzyme functions in the active transport of GSSG as it possibly does in hepatocytes.

Biological Transport↗

Processing enzymes acting on carbohydrate moiety of lysosomal hydrolases in leukemic cells: elevated activity of N-acetylglucosamine-1-phosphotransferase.

We previously demonstrated that an acidic variant form of lysosomal arylsulfatase B accumulated in chronic myelogenous leukemia (CML) cells was highly phosphorylated at its carbohydrate moiety (Uehara Y, et al, Cancer Res 43:5618, 1983). Since lysosomal hydrolases including the sulfatase underwent the posttranslational phosphorylation processing at the carbohydrate moiety, we investigated two enzymes acting on the processing in peripheral leukocytes from leukemia patients. The activity level of the first enzyme in the processing, an N-acetylglucosamine-1-phosphotransferase to form phosphodiester at the carbohydrates, was significantly higher in CML cells than in normal control. The transferase level in CML cells was also higher compared with that in normal bone marrow cells, which include myeloid progenitor cells. However, the activity of the second processing enzyme, a phosphodiester glycosidase that converts a phosphodiester to a phosphomonoester, showed no consistent change in CML cells. Thus, increment of the sulfatase variant containing phosphomonoesters and diesters in CML cells is most probably associated with elevated activities of the phosphotransferase. In two cases of CML in blastic crisis and a case of acute myelogenous leukemia (AML), activity of the processing enzyme was considerably decreased concomitant with reduction of peripheral blastic cells by chemotherapy.

Adult↗

Association of elevated sulfatides and sulfotransferase activities with human renal cell carcinoma.

Lactosylceramide sulfate and galactosylceramide sulfate were found to increase markedly in human renal cell carcinoma (adenocarcinoma) as compared to uninvolved tissue. Activities of two sulfotransferases toward galactosylceramide and lactosylceramide as substrates were significantly elevated in the carcinoma compared to the uninvolved tissue resulting in enhanced synthesis of the two sulfatides in the carcinoma. The elevation of the two sulfotransferases was parallel in most tumors, suggesting that the same enzyme is responsible for the enhanced synthesis of two sulfatides. No consistent difference in the activity of arylsulfatase A, which desulfates the two sulfatides, was observed between the carcinoma and uninvolved tissue. Both the present and previous results show that the increased synthesis of the sulfatide(s) due to elevated sulfotransferase activity could be a biochemical characteristic common to adenocarcinomas derived from different tissues.

Adenocarcinoma↗

An assay method for ganglioside synthase using anion-exchange chromatography.

A rapid procedure which is based on combined ion-exchange chromatography and solubility was established for determination of the activity of ganglioside synthases and cerebroside sulfotransferase. The procedure consists of selective elution of radiolabeled reaction products (acidic glycolipids) freed from labeled precursors and breakdown products on a DEAE-Sephadex column and of direct radioassay of the products in the eluate. Monosialogangliosides were eluted from the column with 40 mM ammonium acetate (AcONH4) in methanol, cerebroside sulfate with 90 mM AcONH4 in methanol, and disialogangliosides with 40 mM AcONH4 in isopropanol/n-hexane/water (55/20/19, v/v/v). The established procedure is simple, reproducible, and economical. Using rat Golgi membrane as enzyme source the recovery rate of the products was over 95%.

Animals↗

Effects of exercise, cold, and immobilization stresses on gamma-glutamyltransferase activity in rat kidney.

Effects of acute and chronic stresses (exercise, cold, and immobilization) on gamma-glutamyltransferase (gamma GT) activity in the rat kidney were investigated. In the extramicrosomal fraction there were significant decreases in acute-exercised rats but significant increases in cold-adapted and immobilized rats. In the microsomal fraction, on the other hand, the gamma GT activity of acute-exercised rats increased definitely. The results suggest that different types of stresses have different effects on gamma GT activity in the rat kidney.

Animals↗

Alterations of protein kinase isozymes in transplantable human lung cancer with special reference to the phosphorylation of arylsulfatase B.

Since a lysosomal arylsulfatase B has been shown to be phosphorylated by a cAMP-dependent protein kinase (cAMP-PK) in transplantable human lung tumor, protein kinase isozymes were investigated in the tumor. Although the kinase of normal human lung comprised both type I and II isozymes at lower level, the tumor kinase was elevated in the activity and occupied almost exclusively by the type II which was responsible for the phosphorylation of arylsulfatase B. The isozyme deviation was also observed in the casein kinase of the tumor with predominance of type II in the tumor in contrast to the coexistence of both types I and II in normal lung.

Casein Kinases↗

Biochemical studies on lymphoblastoid cells with inherited N-acetyl-glucosamine 1-phosphotransferase deficiency (I-cell disease).

Lymphoblastoid cells transformed by Epstein-Barr virus from peripheral lymphocytes of normal individuals and I-cell disease (ICD) patients were used for the enzymic study of lysosomal hydrolases and N-acetylglucosamine 1-phosphotransferase. ICD lymphoblastoid cells secreted a larger amount of hydrolases into medium than normal cells, although the intracellular hydrolases were not deficient in ICD cells. The stimulating effect of 10 mM ammonium chloride on secretion of hydrolases was found only with normal cells, and not with ICD cells, indicating that the hydrolase molecule bearing mannose 6-phosphate was secreted. The ICD lymphoblastoid cells retained the enzymologic characteristics of both lysosomal hydrolases and N-acetylglucosamine 1-phosphotransferase seen in ICD fibroblasts, which allows us to study the pathophysiology of ICD in cells other than fibroblasts.

Adsorption↗