SerpinA7

SerpinA7 is major thyroid hormone transport protein in serum.

SerpinA7 Related Areas

Enzyme>>Protease & Regulator>>Serine Protease & Regulator>>Serpin Superfamily>>SerpinA7

SerpinA7 Alternative Names

SERPINA7, TBG, RP1-82J11.2 [Homo sapiens]

Serpina7, Tbg RP23-228A20.1, C730040N12Rik [Mus musculus]

Summaries for SerpinA7

Entrez Gene summary for SerpinA7:

There are three proteins including thyroxine-binding globulin (TBG), transthyretin and albumin responsible for carrying the thyroid hormones thyroxine (T4) and 3,5,3 -triiodothyronine (T3) in the bloodstream. SerpinA7 gene encodes the major thyroid hormone transport protein, TBG, in serum. It belongs to the serpin family in genomics, but the protein has no inhibitory function like many other members of the serpin family. Mutations in SerpinA7 gene result in TGB deficiency, which has been classified as partial deficiency, complete deficiency, and excess, based on the level of serum TBG. Alternatively spliced transcript variants encoding different isoforms have been found, but the full-length nature of these variants has not been determined.[provided by RefSeq, May 2010]

OMIM - description for SerpinA7:

T4-binding globulin (TBG) is the major thyroid hormone transport protein in man. Inherited abnormalities in the level of serum TBG have been classified as partial deficiency, complete deficiency, and excess. Patients are euthyroid (summary by Mori et al., 1995).

Wikipedia summary for SerpinA7:

Thyroxine-binding globulin (TBG) binds thyroid hormone in circulation. It is one of three proteins (along with transthyretin and albumin) responsible for carrying the thyroid hormones thyroxine (T4) and 3,5,3'-triiodothyronine (T3) in the bloodstream. Of these three proteins, SerpinA7 has the highest affinity for T4 and T3, but is present in the lowest concentration. Despite its low concentration, TBG carries the majority of T4 in the blood. Due to the very low concentration of T4 & T3 in the blood, SerpinA7 is rarely more than 25% saturated with its ligand. Unlike transthyretin and albumin, TBG has a single binding site for T4/T3. SerpinA7 is synthesized primarily in the liver as a 54 kDa protein. In terms of genomics, TBG is a serpin; however, it has no inhibitory function like many other members of this class of proteins.

Human SerpinA7 Protein General Information

 

• Protein names: SerpinA7
• Sequence length: 415 AA.
• Domain: Signal
• Sequence similarities: Belongs to the serpin family.
• Polymorphism: Two qualitative TBG variants occur in particular populations. TBG-A is found in 40% of Australian aborigines, it has reduced affinity for thyroxine and triiodothyroxine and increased susceptibility to inactivation by heat or acid. TBG-S ('s' for slow shift on isoelectic focusing) is found in blacks, Eskimos, Melanesians, Polynesians and Indonesians, but not in Caucasians; TBG-S is slightly more thermolabile.
• Subcellular location: Secreted.
• Tissue specificity: Expressed by the liver and secreted in plasma.
• Involvement in disease: Defects in SERPINA7 are a cause of thyroxine-binding globulin deficiency (TBG deficiency) . Mutations in the SERPINA7 gene can result as a whole spectrum of deficiencies, characterized by either reduced or increased TBG levels in the serum. Patients show, respectively, reduced or elevated protein-bound iodine but are euthyroid.

General information above from UniProt

Function for SerpinA7 Protein

UniProtKB:

SerpinA7 is major thyroid hormone transport protein in serum.

Genatlas:

• serine protease inhibitor, major thyroid hormone transport protein in serum

Phenotype Information for SerpinA7

• Gene/Locus: TBG
• Phenotype: Thyroxine-binding globulin deficiency

Phenotype Information for SerpinA7 from OMIM (Online Mendelian Inheritance in Man)