Protein-bound homocyst(e)ine in normal subjects and in patients with homocystinuria.
A method was developed to quantitate protein-bound homocyst(e)ine using 2-mercaptoethanol. Protein-bound homocyst(e)ine was discovered in the plasma from normal individuals, ranging from 0.5--2.2 nmole/ml. In two obligatory heterozygotes for classical homocystinuria, plasma protein-bound homocyt(e)ine was 3.5 and 4.8 nmole/ml, respectively. Untreated homozygotes showed approximately a 40-fold increase of plasma protein-bound homocyst(e)ine. Furthermore, using conventional methods, no free homocystine was detectable in the supernatant of plasma precipitate from two classical homocystinuric patients treated with pyridoxine, but plasma protein-bound homocyst(e)ine showed a 10-fold increase. Protein-bound homocyst(e)ine was also demonstrated in the liver, kidney, and brain tissues from a patient with methylenetetrahydrofolate reductase deficiency.
D001921:Brain / Q000378:metabolism; D003541:Cystathionine beta-Synthase / Q000172:deficiency; D006579:Heterozygote; D006711:Homocystine / Q000097:blood / Q000378:metabolism; D006712:Homocystinuria / Q000097:blood / Q000378:metabolism*; D006801:Humans; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D011485:Protein Binding
D006711:Homocystine; D003541:Cystathionine beta-Synthase