| Autor: |
Shimojo M; Department of Biochemistry, School of Clinical Pharmaceutical Sciences, Nagasaki University., Sakakibara R, Ishiguro M |
| Jazyk: |
angličtina |
| Zdroj: |
Journal of biochemistry [J Biochem] 1993 Jul; Vol. 114 (1), pp. 83-7. |
| DOI: |
10.1093/oxfordjournals.jbchem.a124144 |
| Abstrakt: |
Human chorionic gonadotropin (hCG) in first trimester placental cells is made up of immature alpha- and beta-subunits containing only N-linked high-mannose sugar chains, which are of 21 kDa for the alpha-subunit and 23 and 19 kDa for the beta-subunit. However, the apparent molecular weight of immature hCG from placental cell extracts has been estimated from gel filtration to be much higher (100-200 kDa; high molecular weight-hCG, HMW-hCG) based on gel filtration than the theoretical value (approximately 44 kDa) of the alpha beta dimer (alpha beta-hCG). We prepared a gel-filtered fraction containing HMW-hCG and investigated treatments for converting it to alpha beta-hCG. We found that the molecular weight of HMW-hCG was decreased to close to that of alpha beta-hCG by treatment with acetone, proteases, or chelating agents. These treatments also shifted the isoelectric point of HMW-hCG from the acidic region (pI = 4-6) to the alkaline (pI = 9-11), approximating to that of alpha beta-hCG. We also found that HMW-hCG, but not acetone-treated HMW-hCG, bound to ATP-agarose resin. These results suggested that the immature alpha beta-hCG molecule in placental cells may be bound to an acidic ATP-binding protein to form HMW-hCG. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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