– WAAG-3R is a bioactive peptide utilized in an ADAMTS-4 (Aggrecanase-1) assay, where aggrecanases, a subset of the ADAMTS (A disintegrin and metalloprotease with thrombospondin motifs) family, target aggrecan, a key structural component of cartilage. Notably, ADAMTS-4 is a principal aggrecanase in human osteoarthritic cartilage. The peptide’s fluorescence resonance energy transfer (FRET) properties are evidenced by an excitation/emission (Ex/Em) spectrum of 340/420 nm.