Abstract
Treatment of intact human erythrocytes with trypsin had no effect upon either the rate of hexose transport or the binding of cytochalasin B to the transport system. In contrast, proteolysis of inside-out vesicles prepared from human erythrocyte membranes inactivated both hexose transport and cytochalasin B binding. When purified hexose transporter, reconstituted into phospholipid vesicles of undetermined size, was treated with trypsin, approx. 50% of the cytochalasin B binding activity was lost. This loss correlated with a decrease in the amount of the transporter polypeptide, as assayed by gel electrophoresis. These results show that the orientation of the transporter can be established through trypsin treatment in conjunction with cytochalasin B binding. Small unilamellar vesicles containing transporter were prepared by sonication of larger species and by a cycle of cholate solubilization and removal of the detergent. In the former case, the transporter orients almost randomly, whereas in the latter approx. 75% of the transporters have the cytoplasmic domain extemal.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
More From: Biochimica et Biophysica Acta (BBA) - Biomembranes
Disclaimer: 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.