DESCRIPTION: This Small Business Innovation Research Phase I project aims to develop new targeted fluorogenic substrates capable of measuring enzyme activities in the Golgi apparatus and Endoplasmic Reticulum (ER) of living cells and tissues. If successful, the proposed research will provide breakthroughs needed to advance the discovery of promising new therapies and modulating drugs for neurodegenerative disorders including Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), Parkinson's disease (PD), Type 2 diabetes, Lowe syndrome, Huntington's disease and allied medical conditions. In Phase I of this project, Marker Gene Technologies, Inc. will establish the feasibility of the technology by preparing new fluorogenic glycosidase, phosphatase and peptidase substrates for enzymes with localized activity in the Golgi and ER and demonstrating differential staining in living cells that are from normal or are of disease origin. In Phase II, these and additional new substrates will be assayed in vitro and in vivo for their ability to measure specific and localized inhibition or induction of these enzymes in living cells as well as differentiate individual enzyme activities in a cell- or tissue-specific manner. The new substrates and the resulting detection systems will provide innovative methods to quantitate Golgi and ER organelle enzyme function and to screen for the influence of secondary drug or protein administration, making them useful analytical tools for drug discovery and diagnosis in a variety of significant medical applications.