Abstract
Free alpha-subunit in normal term placenta was examined for molecular weight, electric charge and ability to combine with standard hCG-beta in comparison with extracellular free alpha-subunit and standard hCG-alpha dissociated from urinary hCG in vitro. The gel chromatography on Sephadex G-100 of the placental extract revealed three major immunoreactive hCG-alpha peaks, designated as P alpha-A (Kav = 0.32-0.46), P alpha-B (0.47-0.58) and P alpha-C (0.59-0.70), near the position of standard hCG-alpha. In the isoelectric focusing, while P alpha-A was mainly distributed over the acidic region, the major components of P alpha-B and P alpha-C were distributed over the basic region. Furthermore, in the combination study with standard hCG-beta, such a alpha-subunit with acidic pI scarcely showed any combining activity whereas alpha-subunit with basic pI revealed significant combining activity. These results suggest the following possibilities: that 1) the various size species of placental alpha-subunit may be responsible for the progressive glycosylation; 2) the small alpha-subunit with basic pI may combine with beta-subunit to form immunoreactive hCG; 3) the alpha-subunit, which has not associated with beta-subunit, may be converted to a large and incombinative form with acidic pI by further glycosylation, followed by secretion as a free alpha-subunit.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
