Assay for Rab geranylgeranyltransferase using size exclusion chromatography

A simple chromatographic assay for Rab geranylgeranyltransferase (Rab GGTas e) has been developed, The method involves separation of the reaction mixtu re on a Sephadex G-25 superfine minicolumn, Addition of 2-propanol to the a ssay results in substantial (similar to 90%) decline of formation of noncov alent lipidprotein complexes, increasing reproducibility and reliability of the method. The activity of Rab prenyltransferase was measured in crude an d partially purified enzyme preparations from wheat seedlings; measurements for several other plants and rat brain cytosol fractions are also presente d, This method can be routinely applied to evaluate the activity of differe nt protein prenyltransferases. (C) 2001 Academic Press.