抄録
The two kinds of glycoprotein hormone α subunit ectopically produced by an undifferentiated carcinoma of the left femoral region (TM-α) and an adenocarcinoma of the right external genitalia (FS-α) were examined for amino acid composition, isoelectric focusing, molecular weight, the ability to combine with standard hCGβ and affinity with lectins (Con A, Ricin and PNA). Both TM-α and FS-α exhibited immunoantigenicity similar to standard hCGα. Furthermore, there were no significant differences in the amino acid compo-sitions of TM-α, FS-α or standard hCGα. In isoelectric focusing, while standard hCGα exhibited a neutral charge, both TM-α and FS-α exhibited strong negative charges. FS-α was as sensitive to sialidase as standard hCGα, whereas most of the TM-α exhibited resistance to sialidase. TM-α contains sialidase-insensitive peripheral material with a negative charge. The affinity with Ricin-Sepharose indicated that most of the FS-α and some of the TM-α may contain terminal sialic acid and the penultimate structure, Galβ1→4GlcNAc; the affinity with PNA-Sepharose indicated that both may also contain terminal sialic acid and the penultimate structure, Galβ1→3GalNAc.
These observations suggest that dissimilar glycosylation processes are present in the carcinoma ectopic biosynthesis of glycoprotein hormone α subunit.
