Evaluation of galactosyltransferase isoenzyme II in a human colon carcinoma-derived cell line, HCT-8.
Polyacrylamide gel electrophoresis of galactosyltransferase (GT) extracted from a human colon adenocarcinoma cell line, HCT-8, demonstrated the presence of two peaks of activity: a slow-moving peak, referred to as GT-II, and a more anodally migrating peak, designated as GT-I, which was also found for normal human serum. However, if GT solubilized from HCT-8 cells was separated by isoelectric focusing, no unique isoenzymes could be detected. Total GT activity from HCT-8 cells was purified by alpha-lactalbumin-Sepharose affinity chromatography followed by ion exchange chromatography on either DEAE-cellulose or FPLC using a Mono Q anion exchange resin. Three major peaks of activity were resolved from anion exchange chromatography. Electrophoresis of each peak revealed a GT pattern identical with that originally observed for the crude (detergent) solubilized homogenate. No enrichment of either GT-I or GT-II was observed in the three enzyme fractions. The data suggest that GT-II may be an artifactual activity of cancer cells composed of GT-I associated with some contaminating protein.
D000230:Adenocarcinoma / Q000201:enzymology; D002460:Cell Line; D002846:Chromatography, Affinity; D002852:Chromatography, Ion Exchange; D003110:Colonic Neoplasms / Q000201:enzymology*; D004340:Drug Contamination; D004591:Electrophoresis, Polyacrylamide Gel; D005700:Galactosyltransferases / Q000302:isolation & purification / Q000378:metabolism*; D006801:Humans; D007525:Isoelectric Focusing; D007527:Isoenzymes / Q000302:isolation & purification / Q000378:metabolism*
D007527:Isoenzymes; D005700:Galactosyltransferases