Human serum albumin (HSA) (HSA)

Human serum albumin (HSA) is the most abundant protein in human plasma, serving as a versatile carrier for a wide range of endogenous ligands and therapeutic drugs (UniProt P02768). "Anchor Site One," scientifically recognized as Sudlow's Site I or the warfarin-binding site, is a large, flexible hydrophobic pocket located in subdomain IIA of the protein's tertiary structure (Ghuman et al., 2005, PubMed). This site is characterized by its preference for bulky, heterocyclic, and negatively charged molecules, making it a primary determinant of the pharmacokinetic profile for many clinical agents (PubChem). HSA plays a vital role in maintaining blood colloid osmotic pressure and acts as a major extracellular antioxidant, neutralizing reactive oxygen species (StatPearls). In drug development, Site I is a critical focus for optimizing drug half-life and volume of distribution, as well as for predicting potential drug-drug interactions resulting from competitive displacement (PubMed: 15911006). Pathological conditions such as liver cirrhosis or nephrotic syndrome can significantly alter HSA concentrations, thereby impacting the free fraction and efficacy of drugs that target this specific anchor site (StatPearls).

Other names

ALBSerum albuminSudlow's Site IWarfarin-binding siteSubdomain IIAAnchor Site One

Non-covalent binding to Sudlow's Site I (Subdomain IIA) to facilitate systemic transport, increase plasma half-life, and regulate the pharmacologically active free fraction of drugs.