globuline

Globulin, also spelled globuline in some sources, refers to a group of water-soluble, globular proteins found in blood plasma and other body fluids. In serum protein analysis, globulins are typically discussed as a set of fractions that separate from albumin during electrophoresis, consisting of alpha, beta, and gamma globulins. The gamma fraction contains most antibodies (immunoglobulins).

Most globulins are produced by the liver (certain alpha and beta globulins, including transferrin, ceruloplasmin, α1-antitrypsin, and α2-macroglobulin) or by plasma cells (gamma globulins, immunoglobulins such as IgG, IgA, and IgM). Globulins serve a variety of roles, including transport of metal ions and lipids, enzyme inhibition, and immune defense. Transferrin and ceruloplasmin transport iron and copper, respectively, while immunoglobulins provide adaptive immunity. Some globulins function as components of the complement system or as protease inhibitors.

Clinically, globulin levels are assessed as part of total protein and can be expressed as the albumin-to-globulin (A/G) ratio. Abnormal globulin patterns may indicate disease. Elevated gamma globulins can be seen in chronic infections, inflammatory or autoimmune diseases, liver disease with increased immunoglobulin production, or monoclonal gammopathies such as multiple myeloma. Decreased globulins may occur with protein-losing conditions, severe malnutrition, or immunodeficiency. The electrophoretic pattern of globulins aids in diagnosis and monitoring of these conditions.

Notes: in some contexts, globuline is used interchangeably with globulin; modern English usage often favors globulin.