Abstract: Peptide ligands having affinity for IgG or for serum albumin are disclosed. Also disclosed are hybrid molecules comprising a peptide ligand domain and an active domain. The active domain may comprise any molecule having utility as a therapeutic or diagnostic agent The hybrid molecules of the invention may be prepared using any of a number techniques including production in and purification from recombinant organisms transformed or transfected with an isolated nucleic acid encoding the hybrid molecule, or by chemical synthesis of the hybrid. The hybrid molecules have utility as agents to alter the elimination half-times of active domain molecules. Elimination half-time is altered by generating a hybrid molecule of the present invention wherein the peptide ligand has binding affinity for a plasma protein.

Abstract: Peptide ligands having affinity for serum albumin are useful for tumor targeting. Conjugate molecules comprising a serum albumin binding peptide fused to a biologically active molecule demonstrate modified pharmacokinetic properties as compared with the biologically active molecule alone, including tissue (e.g., tumor) uptake, infiltration, and diffusion.

Abstract: The present invention provides compounds having formula (I): and pharmaceutically acceptable derivatives thereof, wherein A, B, D, E, G, J, n, and R1 are as described generally and in classes and subclasses herein, and additionally provides pharmaceutical compositions thereof, and methods for the use thereof as caspase inhibitors and for the treatment of disorders caused by excessive apoptotic activity.

Abstract: The present invention is directed to methods of characterizing molecular interaction sites on a biological target molecule. The methods involve contacting a polypeptide with a library of ligand candidates each of which is capable of tethering to the polypeptide at a site of interest, and analyzing the physicochemical properties of the ligand candidates tethering to the polypeptide. The methods herein are useful for discovery of and development of small molecule drugs.

Abstract: The present invention provides compounds having formula (I): 1