Localization of a protein A-tagged Kex2 protein to the vacuole of Saccharomyces cerevisiae allows rapid purification of vacuolar membranes.

We have previously reported an immunoisolation procedure which allows purification of Kex2p-containing Golgi membranes from lysed yeast cells. In order to evaluate the use of tagging procedures in organelle isolation we set out to isolate the same Golgi membrane fraction using a version of the Kex2 protease that had been affinity-tagged at its C-terminus. This protein is found to be localized in the vacuole, providing the basis of a method for the affinity-purification of vacuolar membranes.