The purpose of the this core facility is to provide photo-cleavable 'caged' compounds for use in subprojects within the Program. Compounds with known properties including caged chelators, caged pH probes, caged diacylglycerols and caged inositol phosphates will be made available in highly purified form. Several novel caged peptides, caged diacylglycerols and caged pH probes will be synthesized and characterized by chemical analysis, photolysis, and biochemical assays (enzyme or binding assays). In addition, chemical strategies will be explored for making certain compounds reversibly membrane permeant. The core will provide expertise in chemical synthesis, solid phase peptide synthesis, chemical analysis by nuclear magnetic resonance spectroscopy, UV/Vis absorption spectroscopy, mass spectroscopy, photochemistry and optics. Technical expertise in the use of caged compounds will also be provided including chromatographic analysis of purity, analysis of extents of photoconversion on photolysis, and optimization of photolysis optics for each experimental arrangement.