Protocol measures phosphoRab GTPase dephosphorylation with PPM phosphatases using purified phosphoRab GTPases. Substrates generated by phosphorylating Rab GTPases with MST3 kinase are included.
Method presented for assessing lysosomal enzyme GBA1 activity using Resorufin substrate in low pH conditions to minimize non-lysosomal activity. Validated in GBA1 KO cells, compatible with various lysates and adjustable for different GBA1 levels.