Jl. Ensunsa et al., CATABOLISM OF CYSTEINE, CYSTINE, CYSTEINESULFINATE, AND OTC BY ISOLATED-PERFUSED RAT HINDQUARTER, The American journal of physiology, 264(5), 1993, pp. 782-789
The metabolism of cysteine and related compounds was investigated in t
he isolated perfused hindquarter of the rat. An erythrocyte-based perf
usion medium was used; use of a perfluorochemical emulsion, FC-43, res
ulted in apparent chemical oxidation of cysteine, whereas bovine eryth
rocytes did not appear to contribute significantly to the metabolism o
f cysteine. Rat skeletal muscle perfused with L-[S-35]cysteine, L-[S-3
5]cystine, L-[S-35]cysteinesulfinate, or L-2-oxo-[S-35]thiazolidine-4-
carboxylate (OTC) for 2 h produced [S-35]sulfate and [S-35]taurine. In
all cases, the partitioning of cysteine or cysteinesulfinate between
metabolism to taurine and sulfate was similar, suggesting that cystein
e metabolism in hindquarter may occur via formation and catabolism of
cysteinesulfinate by either cysteinesulfinate decarboxylase or asparta
te (cysteine-sulfinate) aminotransferase. However, the activity of cys
teine dioxygenase was extremely low, suggesting that the conversion of
cysteine to cysteinesulfinate may have been non-enzymatic.