Loop variants of the serpin thyroxine-binding globulin: implications for hormone release upon limited proteolysis

Thyroxine-Binding Globulin Concentrations

Plasma thyroid hormone concentrations may be abnormal in non-thyroid disease and pose diagnostic problems. For example, concentrations of triiodothyronine (T3) in the blood decline in acute illness with a reciprocal increase in reverse triiodothyronine (reverse T3), but thyroxine (T4) concentrations are usually normal or only slightly decreased (1, 2). However, McLarty et al. (3) reported that ...

Absence of large-scale conformational change upon limited proteolysis of ovalbumin, the prototypic serpin.

1H and 31P NMR spectroscopies have been used to examine the effects of limited proteolysis with subtilisin Carlsberg on the global conformation of ovalbumin and on the local environment of phosphoserine 344, a residue two positions removed from the site of proteolysis. Such limited proteolysis has been shown to result in excision of a hexapeptide from the region of the protein that, in other se...

Familial thyroxine-binding globulin deficiency.

Genetically determined thyroxine-binding globulin deficiency is described in two families in the United Kingdom. All subjects in both pedigrees were euthyroid. Transmission was by sex-linkage; males showed low serum protein bound iodine and high thyroxine (T4) resin uptake due to complete absence of serum thryroxine-binding globulin; females were less severely affected. The distinctive biochemi...

Thyroxine-binding globulin, hyperthyroxinemia and hepatocellular carcinoma.

Studies on Human Thyroxine - Binding Globulin

to large volumes of serum may be due to adsorption of neuraminidases to the Sepharose either directly from serum or as the result of bacterial contamination. Partial desialylation of TBG in vivo may be an early step in the catabolism of this protein.