(S,S,S)-AHPC hydrochloride is a von Hippel-Lindau (VHL) amino building block. (S,S,S)-AHPC (Compound 27) is a ligand used as a negative control for (S,R,S)-AHPC. (S,R,S)-AHPC is the VH032-based VHL ligand used in the recruitment of the VHL protein.In Vitro: The VHL protein is a substrate recognition subunit of two ubiquitously expressed and biologically important Cullin RING E3 ubiquitin ligase complexes. VHL is one of the most popular E3 ligases being recruited by bifunctional Proteolysis-targeting chimeras (PROTACs) to induce ubiquitination and subsequent proteasomal degradation of a target protein.