NOVEL AFFINITY LABELS

摘要

The invention provides novel affinity labels for Ser proteases of formula: (Formula 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.