Redox status and protein binding of plasma homocysteine and other aminothiols in patients with hyprhomocysteinemia due to cobalamin deficiency
1994
Mansorr, M.A. | Ueland, P.M. | Svardal, A.M.
We determined reduced, oxidized, and protein-bound homocysteine, cysteine, and cysteinylglycine in plasma from 13 patients with hyperhomocysteinemia (total homocysteine in the range 30.6-159.8 micromoles/L) due to cobalamin deficiency. Reduced homocysteine (mean +/- SD: 1.87 +/- 2.06 micromoles/L) was markedly above normal (0.24 +/- 0.12 micromoles/L) in most patients, and the reduced fraction increased as an exponential function of the total homocysteine concentration. The ratio of reduced homocysteine to total homocysteine was positively correlated with the reduced-total ratio for cysteine and cysteinylglycine, suggesting redox equilibrium between different aminothiol species. The free oxidized and the protein-bound forms of homocysteine account for most of the homocysteine in plasma of these patients. The amount of protein-bound homocysteine was negatively correlated with the concentrations of both protein-bound cysteine and cysteinylglycine, indicating displacement of these aminothiols by homocysteine.
显示更多 [+] 显示较少 [-]