[Comparative study of sialyltransferases in cultured cells of the rat embryo, transformed by DNA bovine adenovirus type 3].
The specific activities of membrane-bound sialyl transferases from six cultures of cells transformed by bovine adenovirus DNA type 3 (BA-3) before and after passage through host animal organism were compared. The sialyl transferase activity was increased with respect to the high molecular weight acceptor, asialylofetuin in the majority of transformed and tumour cultures. Identification of sialylation products by paper chromatography revealed that all cell cultures contain sialyltransferases synthesizing neuraminosyl-alpha (2----6)N-acetyllactosamine. The pH dependence of activities of the membrane-bound enzymes were studied. An additional pH optimum (5.5-6.0) of endogenous activity was revealed in most of transformed cultures. Using isoelectrofocusing of detergent extracts in sucrose density gradient, the presence of multiple forms of the enzyme was revealed in all cultures under study. In most virulent strains, Op2a/4 and OAB2a, the forms possessing a high exogenous activity at pH gradient 6.0-6.5 were activated. The multiple forms of line Op2a/4 were investigated at pH 5.8-6.3 and 7.6-8.0. It was shown that the forms with different pI have different pH optima. A correlation between the changes in the activities of sialyl transferases and the increase of oncogenicity of transformed cells after their passage through host organism was detected only in one group of transformed cells.
D000256:Adenoviridae / Q000201:enzymology*; D000818:Animals; D002417:Cattle; D002472:Cell Transformation, Viral / Q000187:drug effects; D002478:Cells, Cultured; D002854:Chromatography, Paper; D004279:DNA, Viral / Q000378:metabolism*; D004622:Embryo, Mammalian; D005347:Fibroblasts / Q000201:enzymology*; D007525:Isoelectric Focusing; D051381:Rats; D012794:Sialic Acids / Q000494:pharmacology; D012799:Sialyltransferases / Q000378:metabolism*; D014166:Transferases / Q000378:metabolism*
D004279:DNA, Viral; D012794:Sialic Acids; D014166:Transferases; D012799:Sialyltransferases
Sravnitel'noe izuchenie sialiltransferaz v kul'turakh kletok émbrionov krys, transformirovannykh DNK bych'ego adenovirusa tipa 3.