Table III.

Typical Purifications of 5-HT_3A and GABA_A Receptors by FLAG Affinity Chromatography

Receptor	Purification step	Total receptor (nmol)a	Total protein (mg)	Specific activity (pmol/mg)b	Yield (%)c	Average yield (%)d
FLAG-h5-HT3A-1D4	Membranes	34	700	49	100	100
	Solubilized membranes	25	357	68	73	86 ± 16
	Eluted receptor	18	–	–	54	54 ± 13
	Reconstituted receptor	13	5.5	2,300	38	34 ± 7
FLAG-hGABAAα1β3	Membranes	11	324	34	100	100
	Solubilized membranes	8.1	172	47	74	69 ± 13
	Eluted receptor	3.9	1.4	670	35	37 ± 2

^aReceptor concentration estimated as in Table I.

^bFLAG peptide is present in the eluted and purified preparations so that the specific activity given is underestimated by approximately a factor of two (see text).

^cYields are expressed relatively to the starting cell membrane preparation.

^dFigures are mean ± SD for four experiments for 5-HT_3AR purification and three experiments for GABA_AR purification.