I have follwed to isolate the purple membrane from standatd protocol by D. Oesterhelt, W. Stoceckenius,Methods Enzymol. 31 (1974) 667–678. and also I confirmed ratio of Abs280/Abs560 is about 1.8. Now my question is this optical measurment is queit enough to fix the purity of the purple membrane orelse any other confirmation is required.
I have tried another method in this link http://www.ill.eu/sites/deuteration/Protocols/PM_deuteration_protocol.htm