The present invention relates to the preparation and use of therapeutic compounds for the treatment of diseases at specific subcellular target areas such as specific cellular organelles. In particular, the therapeutic compounds of the invention are specific for modifying enzyme activity within targeted organelles or structures of cells and tissues. Subcellular organelles and structures that may be specifically targeted by compounds of the present invention include lysosomes, autophagasomes, the endoplasmic reticulum, the Golgi complex, peroxisomes, the nucleus, membranes and the mitochondria.