A characteristic serpin cleavage product of thyroxine-binding globulin appears in sepsis sera.

Abstract

T4-binding globulin (TBG), the principal thyroid hormone-binding protein of serum, is a member of the serine protease inhibitor (serpin) superfamily. We report a characteristic serpin cleavage product of TBG in sepsis sera. At 49-50 kDa, the TBG remnant is 4-5 kDa smaller than the intact protein and is the same molecular mass as a TBG cleavage product produced by incubation with polymorphonuclear elastase. Incubation with polymorphonuclear leukocytes also produces the 49- to 50-kDa remnant, and this proteolysis is stimulated by zymosan activation. Polymorphonuclear cell cleavage of TBG increases the ratio of free/bound T4. As previously described, in vitro cleavage of TBG by elastase also increases free/bound T4. These findings are consistent with the hypothesis that serine proteases present at inflammatory sites cleave TBG, releasing its hormonal ligands.

• Authors: B Jirasakuldech, G C Schussler, M G Yap, H Drew, A Josephson, J Michl
• Journal: The Journal of clinical endocrinology and metabolism (J Clin Endocrinol Metab) Vol. 85 Issue 11 Pg. 3996-9 (Nov 2000) ISSN: 0021-972X [Print] United States
• PMID: 11095421 (Publication Type: Journal Article)

Chemical References

• Peptide Fragments
• Serpins
• Thyroxine-Binding Proteins
• Pancreatic Elastase
• Thyroxine

Topics

• Adult
• Female
• Humans
• Male
• Molecular Weight
• Neutrophils (metabolism)
• Pancreatic Elastase (metabolism)
• Peptide Fragments (blood, isolation & purification)
• Sepsis (blood)
• Serpins (blood)
• Thyroxine (metabolism)
• Thyroxine-Binding Proteins (metabolism)