- Albumin is the predominant plasma protein. It has no known enzymatic or hormonal activity, and accounts for approximately 50% of the protein found in human plasma.
- Its normal concentrations 35–45g/L. With a molecular weight of about 66kDa, albumin has highly polar nature and dissolves easily in water.
- At pH 7.4, it is an anion with 20 negative charges per molecule; this gives it a high capacity for non-selective binding of many ligands. It also plays a critical role in maintaining colloid osmotic pressure of the plasma.
- The rate of albumin synthesis (14–15g daily) depends on nutritional status, especially on the extent of amino acid deficiencies.
- Its half-life is about 20 days. Importantly, although the albumin level reflects the nutritional status in the longer term, in hospitalized patients the short term changes in plasma albumin concentration are usually due to changes in hydration.