Globulin

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Not to be confused with globin or globular protein.

The globulins are a family of globular proteins that have higher molecular weights and water solubility values than the albumins. Some globulins are produced in the liver, while others are made by the immune system. Globulins, albumin, and fibrinogen are the major blood proteins. The normal concentration of globulins in human blood is about 2.6-4.6 g/dL.

The term "globulin" is sometimes used synonymously with "globular protein". However, albumins are also globular proteins, but are not globulins. All other serum globular proteins are globulins.

Types of globulins[edit]

All globulins fall into one of the following four categories:

Globulins can be distinguished from one another using serum protein electrophoresis.

Reference ranges for blood tests, comparing blood content of globulins (shown in purple at right) with other constituents.

Sizes[edit]

Globulins exist in various sizes. The lightest globulins are the alpha globulins, which typically have molecular weights of around 92 kDa, while the heaviest class of globulins are the gamma globulins, which typically weigh about 120 kDa. Being the heaviest, the gamma globulins are among the slowest to segregate in gel electrophoresis. Since they are immunologically active, they are also called "immunoglobulins".

Non human globulins[edit]

Globulin proteins exist in other species as well, such as in dogs and plants: cucurbitin from squashes and vicilin and legumin from legumes and peas, functioning as protein storage within seeds. These proteins can cause allergic reactions if they bind with human IgE antibodies.[1]

Pseudoglobulins and euglobulins[edit]

Pseudoglobulins are a class of globulins that are more soluble in ammonium sulfate than euglobulins. Pseudoglobulins are also soluble in pure water, while euglobulins are not.[2]

References[edit]

  1. ^ Sanchez-Monge, R.; Lopez-Torrejón, G.; Pascual, C. Y.; Varela, J.; Martin-Esteban, M.; Salcedo, G. (12 November 2004). "Vicilin and convicilin are potential major allergens from pea". Clinical & Experimental Allergy 34 (11): 1747–1753. doi:10.1111/j.1365-2222.2004.02085.x. 
  2. ^ Harris, T; Eagle (1935). "THE IMMUNOLOGICAL SPECIFICITY OF THE EUGLOBULIN AND PSEUDOGLOBULIN FRACTIONS OF HORSE AND HUMAN SERUM". J Gen Physiol 19 (2): 383–396. doi:10.1085/jgp.19.2.383. PMC 2141424. PMID 19872935. 

External links[edit]