Transthyretin (TTR) was previously called
prealbumin because the band it formed on
agarose gel electrophoresis at pH 8.6 was at the
prealbumin position. However, it has been well documented that TTR of rodents does not show a
prealbumin position on electrophoresis. Now, its name describes its function, binding to
retinol binding protein (RBP) and T4. The serum concentration of the
protein is 20-40 mg/dl, and TTR forms a tetramer. The plasma half life of the
protein is 1.9 days. TTR is synthesized by the liver, retina, pancreas, and choroid plexus. In cerebro-spinal fluid (CSF), it is the second most abundant
protein, and is considered as an important
protein in the pathogenesis of
Alzheimer's disease, depression, and lead intoxication. In addition, TTR is a
tryptophan-rich
protein, it is used as one of the nutrition assessment
proteins, it acts as an anti
acute phase protein, and its plasma concentration decreases during
inflammation and
bacterial infection. Since TTR is a highly
amyloidogenic protein because it contains a beta-sheet structure, it becomes a precursor
protein in familial amyloidotic
polyneuropathy(FAP). Moreover, TTR plays important roles in various CNS disorders, diabetes melitus, and lipid metabolism.