Mouse serum albumin (MSA) is the most abundant plasma protein in mice, accounting for approximately 60% of total serum protein. Structurally stabilized by multiple disulfide bonds, albumin serves as the primary regulator of plasma oncotic pressure, helping maintain vascular fluid balance and preventing edema. In addition to its osmotic role, mouse albumin functions as a versatile transport protein, binding and carrying a wide range of endogenous and exogenous ligands, including fatty acids, hormones, metal ions, and numerous small molecules and drugs through specialized hydrophobic binding sites. The free thiol group at Cys34 also contributes to antioxidant defense by scavenging reactive oxygen species.

Altered albumin levels in mice may reflect hepatic dysfunction, renal protein loss, inflammatory states, or nutritional deficiency. Because of its central physiological functions and strong ligand-binding capacity, mouse albumin is widely used in biomedical research involving drug binding, pharmacokinetics, oxidative stress, and protein–ligand interaction studies.