albumiiniin

Albumin is a family of water-soluble proteins that are essential for many physiological processes. In humans, serum albumin is the most abundant protein in blood plasma and plays a key role in maintaining the colloid osmotic (oncotic) pressure that helps keep fluid in the bloodstream. The term albumin exists in different languages; in Finnish, the protein is called albumiini, with albumiiniin being a grammatical form used in context words such as “into albumin.”

Production and structure: Serum albumin is synthesized mainly by hepatocytes in the liver and secreted into plasma, where it has a half-life of about 20 days. Human serum albumin is a single polypeptide chain of about 585 amino acids, with a molecular weight around 66.5 kDa. It consists of three homologous domains and contains a free thiol group at cysteine-34 that contributes to antioxidant properties. Albumin binds and transports a wide range of substances, including fatty acids, hormones, bilirubin, metal ions, and various drugs.

Functions and clinical relevance: The dominant role of albumin is to maintain plasma volume by contributing to oncotic pressure. It also acts as a carrier protein, modulating the distribution and bioavailability of many endogenous and exogenous compounds. Clinically, low serum albumin (hypoalbuminemia) can indicate liver disease, nephrotic syndrome, malnutrition, or chronic inflammation and is associated with poor prognosis in several conditions. High levels (hyperalbuminemia) are uncommon and usually reflect dehydration. Albumin infusions are used in some therapeutic settings to restore volume or protein content.

In laboratories, albumin from different species, especially bovine serum albumin (BSA), is widely used as a standard, blocking agent, or stabilizer in assays and experiments. Egg white contains ovalbumin, another well-known albumin family member used in research and food science.