Bound Homocysteine, Cysteine, and Cysteinylglycine Distribution between Albumin and Globulins

Abstract

Approximately 10%-30%, of protein-bound Hcy, Cys, and CysGly are disulfide-linked to globulins. Amino acids disulfide-linked to albumin are rapidly exchangeable, while exchange of disulfide-linked amino acids from globulins, such as alpha1-acid glycoprotein, is much slower. Consequently, the pools of Hcy, Cys, and CysGly bound to albumin and globulin may represent kinetically and functionally distinct pools. Plasma concentrations of total Hcy and Cys, which are dominated by albumin-bound pools, may not reflect the abundance of functionally significant modifications of globulins.