T. Schlenkrich et al., A RAPID, SIMPLE METHOD FOR THE ISOLATION AND CHARACTERIZATION OF THE PHOTORECEPTOR OF DICTYOSTELIUM-DISCOIDEUM AMEBAS, FEBS letters, 364(3), 1995, pp. 276-278
A membrane-bound 45.5 kDa protein has been isolated from Dictyostelium
discoideum amoebae. It shows an absorption spectrum, which closely re
sembles the action spectrum for amoebal phototaxis, leading to the con
clusion that this protein might play an important role in the photorec
eption of Dictyostelism amoebae, For further characterization we emplo
yed phase partition in an aqueous polymer two-phase system, which was
developed by Widell and Larsson for the separation of plasma membrane
proteins of higher plants, This method clearly shows that the 45.5 kDa
protein is a plasma membrane protein and not an intracellular protein
, Furthermore, by using phase systems with increasing polymer concentr
ations, this simple and rapid purification of plasma membrane proteins
allowed us to isolate the putative photoreceptor in one single step,
Compared to standard biochemical methods phase partition provides an e
normous facilitation of the isolation of D. discoideum membrane protei
ns.