Using a method that measures plasma protein-bound 1/2 cystine, plasma free cyst(e)ine, and urine free cyst(e)ine, we have observed that infants receiving total parenteral nutrition supplemented with cysteine-HCl have significantly higher plasma and urine free cyst(e)ine concentrations (11.3 ± 3.4 μm/dl and 47.2 ± 24.0 μm/dl x̄ ± SD) than when 1/2 cystine concentrations are measured by automated amino acid analysis (7.4 ± 2.0 μm/dl, plasma and 25.0 ± 7.0 μm/dl, urine). These data suggest that both the sulfhydryl and disulfide form of cyst(e)ine must be measured to assess the effect of cysteine-HCl supplemented total parenteral nutrition.
|Original language||English (US)|
|Number of pages||4|
|Journal||American Journal of Clinical Nutrition|
|State||Published - 1983|
ASJC Scopus subject areas
- Food Science
- Medicine (miscellaneous)