Premium
The detection of cysteine‐homocysteine mixed disulphide in plasma of normal fasting man
Author(s) -
GUPTA VATSALA J.,
WILCKEN D. E. L.
Publication year - 1978
Publication title -
european journal of clinical investigation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.164
H-Index - 107
eISSN - 1365-2362
pISSN - 0014-2972
DOI - 10.1111/j.1365-2362.1978.tb00853.x
Subject(s) - homocysteine , homocystinuria , cysteine , methionine , cystathionine beta synthase , chemistry , amino acid , medicine , biochemistry , endocrinology , hemoglobin , enzyme
. Cysteine‐homocysteine mixed disulphide, formed in the degradation of methionine, is detected routinely in the plasma of fasting patients homozygous for homocystinuria and in some obligate heterozygotes. It has not hitherto been identified in the plasma of normal fasting man. Using a highly cross‐linked resin with lithium citrate buffers on a JEOL Amino Acid Analyser, we have detected the mixed disulphide in every one of the plasma samples from twenty normal fasting subjects. The mean concentration was 3.25 μ nol/l (SD 0.85, N = 20), with a range of from 1.68 to 4.85 μ mol/l. The other neutral and acidic amino acids were within the accepted normal range. The study shows that circulating homocysteine is normally not immediately transformed to cystathionine or remethylated, to methionine; some combines with cysteine to form measurable amounts of mixed disulphide. Since homocysteine may produce endothelial damage, the present findings could be relevant to an understanding of the pathogenesis of vascular disease.