Title : A novel form of ectopic human
chorionic gonadotrophin beta-subunit in the serum of a woman with epidermoid cancer
Abstract :
- A novel form of free human chorionic gonadotrophin beta-subunit ( hCG beta ) was found in serum from ElBre, a woman with epidermoid carcinoma of unknown origin
- ElBre hCG beta was larger than standard (pregnancy urine) hCG beta when analysed by gel chromatography (apparent molecular weight 54 000 vs 44 000)
- This size difference appeared to be due to a larger carboxyterminal extension (CTE) of ElBre hCG beta since thermolysin cleavage of the CTE from standard hCG beta and Elbre hCG beta yielded core products of the same size
- Oligosaccharides , O-linked to serine or threonine , were present in ElBre hCG beta , presumably on its CTE as judged by the complete binding of desialylated ElBre hCG beta to immobilized peanut agglutinin (this lectin is specific for terminal galactose linked beta 1----3 to N-acetylgalactosamine, a disaccharide exposed after desialylation of the O-linked oligosaccharides of standard hCG beta )
- ElBre hCG beta , however, was incompletely recognized by antisera specific for the CTE of standard hCG beta , especially the carbohydrate-sensitive antiserum R141
- The O-linked oligosaccharides of standard hCG beta are heterogeneous in size; 13% are of the largest (hexasaccharide) form
- In contrast, over 50% of the O-linked oligosaccharides in hCG beta from the JAr choriocarcinoma cell line are hexasaccharides
- Like desialylated ElBre hCG beta , desialylated JAr hCG beta bound completely to peanut agglutinin , but was incompletely recognized by antisera to the hCG beta-CTE
- Furthermore, JAr hCG beta was intermediate in size between standard hCG beta and ElBre hCG beta when analysed by gel chromatography (apparent molecular weight 49 000)
- (ABSTRACT TRUNCATED AT 250 WORDS