Binds water, Ca(2+), Na(+), K(+), fatty acids, hormones, bilirubin and drugs. Its main function is the regulation of the colloidal osmotic pressure of blood. Major zinc transporter in plasma, typically binds about 80% of all plasma zinc (By similarity). Major calcium and magnesium transporter in plasma, binds approximately 45% of circulating calcium and magnesium in plasma (Probable). Potentially has more than two calcium-binding sites and might additionally bind calcium in a non-specific manner (PubMed:22677715). The shared binding site between zinc and calcium at residue Asp-272 suggests a crosstalk between zinc and calcium transport in the blood (Probable). The rank order of affinity is zinc > calcium > magnesium (Probable). Binds to the bacterial siderophore enterobactin and inhibits enterobactin-mediated iron uptake of E.coli, and may thereby limit the utilization of iron and growth of enteric bacteria such as E.coli (PubMed:6234017). Does not prevent iron uptake by the bacterial siderophore aerobactin (PubMed:6234017). Interacts with FCGRT; this interaction regulates ALB homeostasis (By similarity). Interacts with TASOR (By similarity). In plasma, occurs in a covalently-linked complex with chromophore-bound alpha-1-microglobulin; this interaction does not prevent fatty acid binding to ALB. Plasma. Phosphorylated by FAM20C in the extracellular medium. Can cause allergic reactions in humans. Belongs to the ALB/AFP/VDB family. A peptide arising from positions 165 to 173 was originally termed neurotensin-related peptide (NRP) and was thought to regulate fat digestion, lipid absorption, and blood flow.