Biomaterial Database

Heterogeneity of the human chorionic gonadotropin alpha-subunit secreted by cultured choriocarcinoma (JEG) cells. 1979

R Benveniste, and M C Conway, and D Puett, and D Rabinowitz

The cultured human choriocarcinoma cell line, JEG-clone 3, secretes substantial quantities of both biologically active hCG and an immunoreactive alpha-subunit (JEG-alpha). This study is concerned with a comparative characterization, using RIA, of the chromatographic properties (via gel exclusion and isoelectric focusing) of JEG-alpha and standard urinary hCG-alpha. Most of the molecules comprising the JEG-alpha fraction have an apparent molecular weight greater than that of hCG-alpha. Both hCG-alpha and JEG-alpha exhibit heterogeneity on electrofocusing. However, JEG-alpha contains a major component with an isoelectric pH (pI) of 4.8; this is a minor component, if present at all, in hCG-alpha. The JEG-alpha pI 4.8 component chromatographs with an apparent molecular weight greater than hCG-alpha, while a minor JEG-alpha pI 7.0 component chromatographs with an apparent molecular weight similar to that of the standard. Heterogeneity is expected in the carbohydrate moieties of the glycoprotein hormone subunits. Results of studies on the incorporation of 14C- and 3H labeled amino acids into JEG-alpha suggest that heterogeneity also exists in the protein moiety of JEG-alpha. An interesting possibility is that the form(s) of JEG-alpha with larger apparent molecular weight represents a precursor of the alpha-subunit used to form hCG.

UI	MeSH Term	Description	Entries
D008970	Molecular Weight	The sum of the weight of all the atoms in a molecule.	Molecular Weights,Weight, Molecular,Weights, Molecular
D011247	Pregnancy	The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.	Gestation,Pregnancies
D011863	Radioimmunoassay	Classic quantitative assay for detection of antigen-antibody reactions using a radioactively labeled substance (radioligand) either directly or indirectly to measure the binding of the unlabeled substance to a specific antibody or other receptor system. Non-immunogenic substances (e.g., haptens) can be measured if coupled to larger carrier proteins (e.g., bovine gamma-globulin or human serum albumin) capable of inducing antibody formation.	Radioimmunoassays
D011956	Receptors, Cell Surface	Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behavior of the target cell (From Alberts, Molecular Biology of the Cell, 2nd ed, pp693-5). Cell surface receptors, unlike enzymes, do not chemically alter their ligands.	Cell Surface Receptor,Cell Surface Receptors,Hormone Receptors, Cell Surface,Receptors, Endogenous Substances,Cell Surface Hormone Receptors,Endogenous Substances Receptors,Receptor, Cell Surface,Surface Receptor, Cell
D002250	Carbon Radioisotopes	Unstable isotopes of carbon that decay or disintegrate emitting radiation. C atoms with atomic weights 10, 11, and 14-16 are radioactive carbon isotopes.	Radioisotopes, Carbon
D002460	Cell Line	Established cell cultures that have the potential to propagate indefinitely.	Cell Lines,Line, Cell,Lines, Cell
D002822	Choriocarcinoma	A malignant metastatic form of trophoblastic tumors. Unlike the HYDATIDIFORM MOLE, choriocarcinoma contains no CHORIONIC VILLI but rather sheets of undifferentiated cytotrophoblasts and syncytiotrophoblasts (TROPHOBLASTS). It is characterized by the large amounts of CHORIONIC GONADOTROPIN produced. Tissue origins can be determined by DNA analyses: placental (fetal) origin or non-placental origin (CHORIOCARCINOMA, NON-GESTATIONAL).	Choriocarcinomas
D005260	Female		Females
D006063	Chorionic Gonadotropin	A gonadotropic glycoprotein hormone produced primarily by the PLACENTA. Similar to the pituitary LUTEINIZING HORMONE in structure and function, chorionic gonadotropin is involved in maintaining the CORPUS LUTEUM during pregnancy. CG consists of two noncovalently linked subunits, alpha and beta. Within a species, the alpha subunit is virtually identical to the alpha subunits of the three pituitary glycoprotein hormones (TSH, LH, and FSH), but the beta subunit is unique and confers its biological specificity (CHORIONIC GONADOTROPIN, BETA SUBUNIT, HUMAN).	Chorionic Gonadotropin, Human,HCG (Human Chorionic Gonadotropin),Biogonadil,Choriogonadotropin,Choriogonin,Chorulon,Gonabion,Human Chorionic Gonadotropin,Pregnyl,Gonadotropin, Chorionic,Gonadotropin, Human Chorionic
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man