Corticosteroid-binding globulin (CBG) also known as transcortin or serpin A6 is a protein that in humans is encoded by the SERPINA6 gene.

This gene encodes an alpha-globulin protein with corticosteroid-binding properties. This is the major transport protein for glucorticoids and progestins in the blood of most vertebrates. The gene localizes to a chromosomal region containing several closely related serine protease inhibitors which may have evolved by duplication events. [provided by RefSeq, Jul 2008]. Publication Note: This RefSeq record includes a subset of the publications that are available for this gene. Please see the Gene record to access additional publications.
Function: Major transport protein for glucocorticoids and progestins in the blood of almost all vertebrate species.