globulin

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globulin,

any of a large family of proteinsprotein,
any of the group of highly complex organic compounds found in all living cells and comprising the most abundant class of all biological molecules. Protein comprises approximately 50% of cellular dry weight.
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 of a spherical or globular shape that are widely distributed throughout the plant and animal kingdoms. Many of them have been prepared in pure crystalline form. The term globulin is a partly procedural one, used in classifying an otherwise diverse group of proteins that are soluble in water or dilute salt solutions. Among the most important are the immunoglobulins (Ig), the antibodies of the immune system (see immunityimmunity,
ability of an organism to resist disease by identifying and destroying foreign substances or organisms. Although all animals have some immune capabilities, little is known about nonmammalian immunity.
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). They are classified into five types based upon structure: IgA, IgD, IgE, IgG, and IgM. IgG or &ggr;-globulin is the most common and forms about 70% of the immunoglobins in the blood. Other globulins are involved in the transport of a variety of substances, including lipidslipids,
a broad class of organic products found in living systems. Most are insoluble in water but soluble in nonpolar solvents. The definition excludes the mineral oils and other petroleum products obtained from fossil material.
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, hormoneshormone,
secretory substance carried from one gland or organ of the body via the bloodstream to more or less specific tissues, where it exerts some influence upon the metabolism of the target tissue.
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, and inorganic ions.

Globulin

A general name for any member of a heterogeneous group of serum proteins precipitated by 50% saturated ammonium sulfate. See Protein, Serum

The introduction of electrophoresis during the 1930s permitted subdivision of the globulins into alpha, beta, and gamma globulins on the basis of relative mobility at alkaline pH (8.6). However, each of these subgroups, though electrophoretically homogeneous, consists of a great variety of proteins with different biological properties and markedly different sizes and chemical properties other than net charge. Thus the α2-globulins, for example, as defined by moving boundary or paper electrophoresis, contain proteins ranging in molecular weight from approximately 50,000 to approximately 1,000,000 (α2-macroglobulin), each with differing functions. See Immunoglobulin

globulin

[′gläb·yə·lən]
(biochemistry)
A heat-labile serum protein precipitated by 50% saturated ammonium sulfate and soluble in dilute salt solutions.

globulin

any of a group of simple proteins, including gamma globulin, that are generally insoluble in water but soluble in salt solutions and coagulated by heat
References in periodicals archive ?
Thyroid hormone binding in serum of 15 vertebrate species: isolation of thyroxine-binding globulin and prealbumin analogs.
Thyroxine-protein interactions: interaction of thyroxine and triiodothyronine with human thyroxine-binding globulin.
In cases of patients with low albumin concentration, altered thyroxine-binding globulin concentration and abnormal thyroid hormone-binding protein measurement of [FT.
3] Thyroxine-binding globulin Thyroglobulin Thyroid-stimulating immunoglobulins Antithyroglobulin antibodies Antithyroid peroxidase antibodies TABLE 2 Factors and Conditions That Alter Thyroxine Binding Globulin (TBG) Levels Increase TBG Level Decrease TBG Level Congenital Congenital Pregnancy Androgens Oral estrogens Nephrotic syndrome Estrogen-secreting tumors Cirrhosis Acute hepatitis L-asparaginase Primary biliary cirrhosis Glucocorticoids Narcotics (heroin, methadone, hydrocodone) Clofibrate 5-fluorouracil Acute intermittent porphyria TABLE 3.
It is proposed that lack of high-affinity thyroid-hormone-binding proteins, that is, thyroxine-binding globulin, in the adult rat plays a role, leading to increased availability of [T.
Different competition of thyroxine binding to transthyretin and thyroxine-binding globulin by hydroxy-PCBs, PCDDs and PCDFs.
A pool of normal human serum with thyroxine-binding globulin (TBG; 17 mg/L), transthyretin (0.
4]), cortisol, progesterone, and thyroxine-binding globulin (TBG) were also measured on the IMMULITE 2500 analyzer but by competitive immunoassays using limiting amounts of immobilized antibodies and labeled hormones.
The vast preponderance of circulating thyroid hormones are bound to 3 classes of plasma proteins: thyroxine-binding globulin (TBG) [3] transthyretin (TTR; also termed thyroxine-binding prealbumin), and albumin (1).
The sBC was further assessed by measuring the concentration of thyroxine-binding globulin (TBG), the main [T.