Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.48 (transcriptase)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We studied the beta-1,3-galactosyltransferase (GalT) and alpha-1,2-fucosyltansferase (FT) involved in the biosynthesis of type-1-chain carbohydrate antigens in human colon adenocarcinoma cell lines. We detected a GalT activity able to use GlcNAc as acceptor and found that lacto-N-biose I (Galbeta1-3GlcNAc) is the only reaction product. Such beta1,3GalT is kinetically similar to a pig trachea enzyme involved in mucin synthesis. The specific activity is high in cells that react strongly with anti-Lewis a and anti-Lewis b antibodies, and undetectable in a cell line that lacks antibody reaction. Reverse-transcriptase-mediated PCR analysis followed by DNA sequencing indicated that secretor-type alpha1,2FT is expressed in the cells, while the H type alpha1,2FT is not. The apparent Km values for donor and acceptor substrates determined for alpha1,2FT are similar to those of secretor-type alpha1,2FT and the specific activity measured correlates with Lewis b antigen expression on the cell surface. Moreover, some of the cell lines express Lewis y and H type 2 antigens, indicating that secretor type alpha1,2FT is responsible for their synthesis. Results suggest that biosynthesis of type-1-chain tumor-associated antigens in human colon carcinoma cells is operated by secretor-type alpha1,2FT, as reported in normal mucosa, and that beta1,3GalT activity may play a relevant role in its control.
 ...
PMID:Beta-1,3-galactosyltransferase and alpha-1,2-fucosyltransferase involved in the biosynthesis of type-1-chain carbohydrate antigens in human colon adenocarcinoma cell lines. 976 Jan 91