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DOI: 10.1055/s-2002-23490
© Johann Ambrosius Barth
Thermal destabilization of ovarian LH/hCG receptors by negatively charged lipids
Publikationsverlauf
received 08 August 2000
first decision 10 November 2000
accepted 26 September 2001
Publikationsdatum:
27. März 2002 (online)
Summary
The stabilizing effect of BSA on the rat ovarian LH/hCG receptor was analyzed by thermal perturbation technique. Thermal destabilization of the receptor with arachidonic acid along with digestion of membrane with phospholipase A2 and reversal of these effects when BSA was used as fatty acids scavenger, may indicate that free fatty acids are responsible for instability of the LH/hCG receptor. This destabilizing effect may be caused by the presence of a net negative surface charge provided by fatty acids. This presumption was corroborated by the reconstitution of delipidated LH/hCG receptor into proteoliposomes. Delipidated receptor lost to a great extent its binding activity and thermal stability. The receptor was fully reactivated by the reconstitution into proteoliposomes with neutral phosphatidylcholine but not with negatively charged phosphatidylserine and phosphatidylglycerol. Thermal inactivation of the LH/hCG receptor by delipidation was entirely inverted by treatment with phosphatidylcholine but the presence of negatively charged phospholipids did not change the heat inactivation profile of hCG-binding sites.
Key words:
LH/hCG receptor - Thermal inactivation - Fatty acids - Proteoliposomes - Phospholipids
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Jaroslav Kolena
Institute of Experimental Endocrinology
Slovak Academy of Sciences
Vlarska 3
83306 Bratislava
Slovak Republic
Fax: +4217 54772800
eMail: ueenkole@savba.savba.sk