Abstract
The delipidated Ca ++-ATPase prepared from intestinal brush border membranes showed a higher activity of Ca ++-independent ATPase, a lower Km value for ATP and a higher Km value for Ca ++ than its original membrane Ca ++-ATPase. The addition of phosphatidylcholine re-activated the delipidated Ca ++-ATPase to approximately 89 % of its original membrane Ca ++-ATPase activity but did not restore the affinity for Ca ++. This phospholipid raised the Km value for ATP but had little effect on the Km value for Ca ++. Palmitic acid elevated the Km value for Ca ++ but did not change the Km value for ATP. Kinetic analyses of these data suggest that the hydrocarbon chain of phosphatidylcholine is an important rate-limiting factor for the access of Ca ++ to the enzyme and the polar head groups of phosphorylcholine and ester bond may be the factor for the access of ATP.
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.
