Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.4.99.7 (sialyltransferase)
 1,534 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have examined the role of CMP-NeuAc:Gal beta 1-3GalNAc-R alpha(2-3)-sialyltransferase in fresh leukemia cells and leukemia-derived cell lines. Enzyme activity in normal granulocytes using Gal beta 1-3GalNAc alpha-o-nitrophenyl as substrate was 1.5 +/- 0.7 nmol/mg/h whereas activity in morphologically mature granulocytes from 6 patients with chronic myelogenous leukemia (CML) was 4.2 +/- 1.6 nmol/mg/h (P less than 0.05). Myeloblasts from 5 patients with CML in blast crisis showed enzyme activity levels of 6.5 +/- 2.5 nmol/mg/h. From 2 patients with CML, both blasts and granulocytes were obtained, with higher enzyme activity in the patients' blasts (7.1 nmol/mg/h) than in their granulocytes (4.9 nmol/mg/h) in both cases, suggesting that the increase in enzyme activity is related to the differentiation or proliferation status of the CML cells. However, similarly high enzyme levels were also seen in myeloblasts from acute myeloblastic leukemia patients (5.6 +/- 1.4 nmol/mg/h) and in some acute myeloblastic leukemia-derived cell lines (KG1a and HL60), suggesting that increased levels of this enzyme are not directly correlated with the presence of the Ph1 chromosome. This alpha(2-3)-sialyltransferase activity can also be detected in normal peripheral blood lymphocytes and exhibits increased activity in chronic lymphocytic leukemia cells and acute lymphoblastic leukemia. These data suggest that the level of enzyme activity may vary with growth rate and maturation status in myeloid and lymphoid hemopoietic cells. Finally, we have identified a glycoprotein in acute myeloblastic leukemia cells that serves as a substrate for the alpha(2-3)-sialyltransferase. The desialylated form of the glycoprotein was resialylated in vitro by the purified placental form of this alpha(2-3)-sialyltransferase and exhibits a molecular weight of about 150,000.
 ...
PMID:Human leukemic myeloblasts and myeloblastoid cells contain the enzyme cytidine 5'-monophosphate-N-acetylneuraminic acid:Gal beta 1-3GalNAc alpha (2-3)-sialyltransferase. 237 65

The level of sialyltransferase activity in leukaemic blasts from acute lymphoblastic leukaemia (ALL) cases was significantly lower (3.29 +/- 2.09 pmoles/5 X 10(7) cells or 1.77 +/- 1.16 pmoles/mg protein) than those (18.80 +/- 4.91 pmoles/5 X 10(7) cells or 7.72 +/- 1.75 pmoles/mg protein) of mature lymphocytes from normal volunteers (T less than 0.001). An inverse relationship between the level of sialyltransferase activity and the level of terminal transferase (TdT)activity was seen in blasts from eight TdT-positive ALL cases. No significant difference was observed in the level of sialyltransferase activity between ALL and cells of chronic myelogenous leukemia (CML) in blast crisis. Short Term culture of ALL blast cells with 12-0-tetradecanoylphorbol-13-acetate (TPA) at the concentration of 10-(6)M to 10-(9)M caused a marked increase in sialyltransferase activity. In one of these three ALL cases the population of TdT-positive cells and the TdT activity of the blasts decreased significantly after culture with TPA. These results suggest that biochemical differentiation of leukaemic lymphoblasts has been induced by the addition of TPA, although morphological changes were not observed. Sialyltransferase activity may be a useful indicator for the analysis of differentiation of lymphocytes.
 ...
PMID:Sialyltransferase activity as a marker for the differentiation of lymphocytes. Increase in sialyltransferase activity of blasts from acute lymphoblastic leukaemia cases by 12-o-tetradecanoylphorbol-13-acetate (TPA). 695 64