Abstract: The invention provides novel affinity labels for Ser proteases of formula: L-A-X—NH—CH(R?)C(?O)CH2Cl??(I) wherein L, A, X, and R? have any of the values defined in the specification, or salts thereof, as well as compositions comprising such compounds or salts. The composition of the amino acid side-chain (R?) along with the amino acid or amino acid sequence (peptide) of the X component of formula I, affect the target selectivity of the labeled affinity ligand. Utilization of cell permeable, enzyme selective, labeled affinity ligands, provides a precise mechanism for evaluating the current and future status of cell populations.

Abstract: The invention provides assay methods and reagents useful for evaluating the level of enzyme activities within living cells. Enzyme activity levels within living cells, such as Serine proteases, can be key determinates in assessing; 1) the presence of tumor (cancer) cells, 2) the predictive efficacy of a chemotherapeutic treatment regimen using a particular therapeutic agent or process, 4) the probability of graft rejection or acceptance, and 5) the disease state status of a cell. The identification of the up or down regulation relationships of serine proteases within living cell systems, provides a rapid, yet finely tuned mechanism for predicting the current and future physiological state of these cell populations.

Abstract: The invention provides assay methods and reagents useful for evaluating the level of enzyme activities within living cells. Enzyme activity levels within living cells, such as caspases and Serine proteases, can be key determinates in assessing; 1) the apoptotic state of a cell, 2) the presence of tumor (cancer) cells, 3) the predictive efficacy of a chemotherapeutic treatment regimen using a particular therapeutic agent or process, 4) the probability of graft rejection or acceptance, identification of the up or down regulation relationships of serine proteases and caspases within living cell systems, provides a rapid, yet finely tuned mechanism for predicting the current and future state of these cell populations, and 5) the disease state status of a cell.