S-Homocysteinylated Proteins - Homocysteine in Protein Structure/Function and Human Disease - page 119

Fig. 7.1 HPLC analysis of thiol-containing amino acids released from globulin (top panel)or
albumin (bottom panel) fractions of serum. Peaks are indicated as Cys (cysteine), Hcy (homocys-
teine), CysGly (cysteinylglycine), and GSH (glutathione). The vertical axis shows fluorescence
detector response in millivolts (Reproduced from [106])

7.1.2 S -Hcy-Transthyretin

Transthyretin (TTR) is a minor plasma protein that occurs at concentrations
0.2-0.4 mg/mL, about 200-fold lower than serum albumin. In human plasma,
TTR exists as a homotetramer of 13.8-kDa subunits, each of which has a single
Cys 10 residue. TTR transports the hormone thyroxine and the retinol-binding
protein-retinol complex [413] and has been linked to the formation of amyloid
deposits in familial TTR amyloidosis, senile systemic amyloidosis [414], and
familial amyloidotic polyneuropathy [415].