Abstract
hCG is a glycoprotein hormone composed of two dissimilar subunits, α and β, joined non-covalently. The hormone, in addition to having N-linked sugar units, two on each subunit, contains four O-linked structures, all attached to the COOHsegment of the β subunit (Birken and Canfield, 1977; Cole et al., 1985). Gonadotropin large free α (LFA) is an oversized (Mr=24,000) non-combining form of the glycoprotein hormone common α-subunit (Mr=22,000). LFA can contain a single O-linked sugar unit attached to Thr 39 which may in part account for its size difference with the α-subunit incorporated into glycoprotein hormones (Cole et al, 1984a; Parsons and Pierce, 1984). Both hCG and LFA are secreted by the normal trophoblast in pregnancy and by the neoplastic trophoblast in hydatidiform mole and choriocarcinoma (Hussa, 1981; Cole et al., 1983; Cole et al., 1984b).
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References
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Cole, L.A. (1987). O-Glycosylation of Proteins in the Normal and Neoplastic Trophoblast. In: Miller, R.K., Thiede, H.A. (eds) Cellular Biology and Pharmacology of the Placenta. Trophoblast Research. Springer, Boston, MA. https://doi.org/10.1007/978-1-4757-1936-9_10
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DOI: https://doi.org/10.1007/978-1-4757-1936-9_10
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