Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
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Target Concepts:
Gene/Protein
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Query: EC:2.4.99.6 (
sialyltransferase
)
1,546
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Sialyltransferase activities, SAT-3 (CMP-NeuAc:nLcOse4Cer alpha 2-3sialyltransferase) and SAT-4 (CMP-NeuAc:GgOse4Cer alpha 2-3sialyltransferase), in Colo 205 cells catalyze the transfer of sialic acid to the terminal galactose of GlcNc-- and GalNAc-containing glycolipid substrates, respectively. Competition kinetic studies with nLcOse4Cer and GM1 as substrates in a
sialyltransferase
assay show that these two activities are catalyzed by two different catalytic entities. The two enzymes were co-solubilized with taurochlorate and resolved by DEAE--Cibacron Blue--Sepharose column chromatography into two elution peaks. The column eluent with SAT-3 activity failed to transfer sialic acid to asialo alpha(1)-acid glycoprotein, indicating that this enzyme is different from the
sialyltransferase
(ST3N) that synthesizes NeuAc alpha 2-3Gal linkage in asparagine-linked oligosaccharides of glycoprotein. However, SAT-3 activity can be immunoprecipitated with a polyclonal antibody produced against a protein expressed in Escherichia coli as GST-fusion protein from an ECB cDNA homolog of an alpha 2-3 sialyltransferase SAT-3 or
STZ
) the has been cloned from human melanoma cell and human placenta. Thus a concentration-dependent decrease in the residual SAT-3 activity relative to SAT-4 activity was observed in the supernatant after precipitation of the immune complex. Expression of SAT-3 (
STZ
) cDNA was also detected in Colo 205 cell by RT-PCR, followed by sequence analysis of the RT-PCR product. Characterization of the catalytic reaction products of SAT-3 and SAT-4 with thin-layer chromatography, sialidase treatment, and binding to specific antibodies indicates that both SAT-3 and SAT-4 catalyze the formation of alpha 2-3 linkage between sialic acid and terminal galactose of glycolipid substrates.
...
PMID:Characterization of two glycolipid: alpha 2-3sialyltransferases, SAT-3 (CMP-NeuAc:nLcOse4Cer alpha 2-3sialyltransferase) and SAT-4 (CMP-NeuAc:GgOse4Cer alpha 2-3sialyltransferase), from human colon carcinoma (Colo 205) cell line. 861
Alteration of
sialyltransferase
expression has been implicated in carcinogenesis. Out of sialyltransferases cloned to date, we focused on ST3Gal IV expression in human renal cell carcinoma (RCC). Levels of ST3Gal IV mRNA were examined in human RCC in comparison with non-tumor kidney. ST3Gal IV cDNA obtained by polymerase chain reaction from cDNA library of human RCC cell line ACHN was identical to
STZ
in nucleotide sequence. Northern blot analysis was performed for 24 non-tumor kidney and 25 primary RCC tissues, and 5 metastases. ST3Gal IV mRNA level was decreased in 16 cases of 22 primary RCC tissues compared to 21 non-tumor kidney tissues. The mRNA level was low in 4 and equivocal in one, of 5 metastases. The 6 cases that possessed almost the same levels of ST3Gal IV mRNA in primary tumor tissues as those in non-tumor kidneys showed favorable prognoses, as assessed by Kaplan-Meier curve. These results indicate that down-regulation of ST3Gal IV mRNA may be one of the factors associated with the malignant progression of human RCC.
...
PMID:Clinical significance of ST3Gal IV expression in human renal cell carcinoma. 1237 29
