Abstract
The role of carbohydrate in the heterogeneity of hCG and its subunits is unclear. To study this question, we chromatographed over Sephadex G-100 an extract of term placenta as well as sera from a woman in the first and third trimesters of pregnancy and sera from two patients with nontrophoblastic malignancies. Samples were cochromatographed with radiolabeled urinary standards. hCG from first trimester pregnancy serum showed multiple peaks on G-100. The dominant peak eluted with an apparent molecular weight (72,000) higher than that of hCG from third trimester serum (63,000), urine (61,000), and placenta (59,000). hCG from both malignancy sera eluted with an apparent molecular weight (62,000) similar to that of hCG from third trimester and urinary hCG. Free hCGα from all sera eluted with a similar apparent molecular weight (29,000), which was higher than that of placental and urinary free α-subunit (22,000) and the α-subunit dissociated from intact hCG from all sources (22,000-23,000). The subunits were dissociated in the denaturing medium of 6 M guanidine-HCl, pH 3.0, and chromatographed in this medium over Sepharose CL-6B. This eliminated all of the differences in apparent molecular weight among corresponding forms that were found on G-100. All forms of hCGα coeluted with a chemically identified 80% deglycosylated hCGα. hCG and free α-subunits were incubated with mixed exoglycosidases which lacked detectable protease activity and were then rechromatographed on G-100. After deglycosylation, hCG from different sources eluted with a considerable heterogeneity (mol wt range, 40,000-50,000) not present in the native forms. Despite the heterogeneity of native free α-subunit from various sources, deglycosylation produced a common species with apparent molecular weights of 11,000-12,000, close to the chemically determined molecular weight of the polypeptide chain (10,400). These studies suggest that 1) ectopic serum hCG and free α-subunit are similar to corresponding eutopic forms; 2) serum hCG and free α-subunit from all sources are more glycosylated than placental or urinary forms; 3) first trimester hCG is more glycosylated than other forms of hCG; and 4) serum free α-subunit is more glycosylated than the α-subunit which combines with hCGβ to form intact hCG.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1111-1120 |
| Number of pages | 10 |
| Journal | Journal of Clinical Endocrinology and Metabolism |
| Volume | 50 |
| Issue number | 6 |
| State | Published - 1980 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Biochemistry
- Endocrinology, Diabetes and Metabolism
Cite this
Increased glycosylation of serum human chorionic gonadotropin and subunits from eutopic and ectopic sources : Comparison with placental and urinary forms. / Fein, H. G.; Rosen, S. W.; Weintraub, B. D.
In: Journal of Clinical Endocrinology and Metabolism, Vol. 50, No. 6, 1980, p. 1111-1120.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Increased glycosylation of serum human chorionic gonadotropin and subunits from eutopic and ectopic sources
T2 - Comparison with placental and urinary forms
AU - Fein, H. G.
AU - Rosen, S. W.
AU - Weintraub, B. D.
PY - 1980
Y1 - 1980
N2 - The role of carbohydrate in the heterogeneity of hCG and its subunits is unclear. To study this question, we chromatographed over Sephadex G-100 an extract of term placenta as well as sera from a woman in the first and third trimesters of pregnancy and sera from two patients with nontrophoblastic malignancies. Samples were cochromatographed with radiolabeled urinary standards. hCG from first trimester pregnancy serum showed multiple peaks on G-100. The dominant peak eluted with an apparent molecular weight (72,000) higher than that of hCG from third trimester serum (63,000), urine (61,000), and placenta (59,000). hCG from both malignancy sera eluted with an apparent molecular weight (62,000) similar to that of hCG from third trimester and urinary hCG. Free hCGα from all sera eluted with a similar apparent molecular weight (29,000), which was higher than that of placental and urinary free α-subunit (22,000) and the α-subunit dissociated from intact hCG from all sources (22,000-23,000). The subunits were dissociated in the denaturing medium of 6 M guanidine-HCl, pH 3.0, and chromatographed in this medium over Sepharose CL-6B. This eliminated all of the differences in apparent molecular weight among corresponding forms that were found on G-100. All forms of hCGα coeluted with a chemically identified 80% deglycosylated hCGα. hCG and free α-subunits were incubated with mixed exoglycosidases which lacked detectable protease activity and were then rechromatographed on G-100. After deglycosylation, hCG from different sources eluted with a considerable heterogeneity (mol wt range, 40,000-50,000) not present in the native forms. Despite the heterogeneity of native free α-subunit from various sources, deglycosylation produced a common species with apparent molecular weights of 11,000-12,000, close to the chemically determined molecular weight of the polypeptide chain (10,400). These studies suggest that 1) ectopic serum hCG and free α-subunit are similar to corresponding eutopic forms; 2) serum hCG and free α-subunit from all sources are more glycosylated than placental or urinary forms; 3) first trimester hCG is more glycosylated than other forms of hCG; and 4) serum free α-subunit is more glycosylated than the α-subunit which combines with hCGβ to form intact hCG.
AB - The role of carbohydrate in the heterogeneity of hCG and its subunits is unclear. To study this question, we chromatographed over Sephadex G-100 an extract of term placenta as well as sera from a woman in the first and third trimesters of pregnancy and sera from two patients with nontrophoblastic malignancies. Samples were cochromatographed with radiolabeled urinary standards. hCG from first trimester pregnancy serum showed multiple peaks on G-100. The dominant peak eluted with an apparent molecular weight (72,000) higher than that of hCG from third trimester serum (63,000), urine (61,000), and placenta (59,000). hCG from both malignancy sera eluted with an apparent molecular weight (62,000) similar to that of hCG from third trimester and urinary hCG. Free hCGα from all sera eluted with a similar apparent molecular weight (29,000), which was higher than that of placental and urinary free α-subunit (22,000) and the α-subunit dissociated from intact hCG from all sources (22,000-23,000). The subunits were dissociated in the denaturing medium of 6 M guanidine-HCl, pH 3.0, and chromatographed in this medium over Sepharose CL-6B. This eliminated all of the differences in apparent molecular weight among corresponding forms that were found on G-100. All forms of hCGα coeluted with a chemically identified 80% deglycosylated hCGα. hCG and free α-subunits were incubated with mixed exoglycosidases which lacked detectable protease activity and were then rechromatographed on G-100. After deglycosylation, hCG from different sources eluted with a considerable heterogeneity (mol wt range, 40,000-50,000) not present in the native forms. Despite the heterogeneity of native free α-subunit from various sources, deglycosylation produced a common species with apparent molecular weights of 11,000-12,000, close to the chemically determined molecular weight of the polypeptide chain (10,400). These studies suggest that 1) ectopic serum hCG and free α-subunit are similar to corresponding eutopic forms; 2) serum hCG and free α-subunit from all sources are more glycosylated than placental or urinary forms; 3) first trimester hCG is more glycosylated than other forms of hCG; and 4) serum free α-subunit is more glycosylated than the α-subunit which combines with hCGβ to form intact hCG.
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M3 - Article
C2 - 7372790
AN - SCOPUS:0018925634
VL - 50
SP - 1111
EP - 1120
JO - Journal of Clinical Endocrinology and Metabolism
JF - Journal of Clinical Endocrinology and Metabolism
SN - 0021-972X
IS - 6
ER -