Purification of GTP gamma S binding proteins from membranes of porcine brain using convective interaction media (CIM (R)) supports

Membranes from porcine brain bind relatively large quantities of guanosine 5'-(3-0-thio) triphosphate (GTP gamma S), a poorly-hydrolysable analogue of GTP. Chromatography of solubilized proteins with 1% Sodium cholate using C IM(R) DEAE column (Convective Interaction Media) revealed two fractions rea ch in GTP gamma S binding proteins. In reduced SDS-PAGE analysis only these two fractions showed a protein band with molecular mass 42 kDa which corre sponded to alpha subunits G(s), G(i) or G(11). Comparison between CIM(R) DE AE and traditional DEAE-Sephacel methods showed that membrane bound heterot rimeric G-proteins might be isolated by HPLC using CIM(R) supports on secon d or minute time scale.