ISSN:
0306-042X
Keywords:
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The incorporation of deuterated serine into cysteine during the metabolism of cystine by Escherichia coli was studied in order to determine the extent to which the carbon-sulfur bond(s) of the cystine is cleaved. The results indicate that the major route (∽80%) for cystine metabolism consists of a reductive cleavage of the cystine disulfide bond to form cysteine. Evidence is presented which shows that a portion of the remaining cystine is broken down by a pathway(s) which results in cleavage of the carbon-sulfur bond of the cystine. This pathway would be the same as that expected for the β-elimination of pyruvate from cystine catalysed by the enzyme β-cystathionase. In addition, a small portion of the resulting cysteine is shown to undergo a reversible dissociation to serine and hydrogen sulfide. Evidence is presented which shows that this dissociation is caused by the enzyme cysteine synthetase [O-acetyl-L-serine acetate-lyase (adding H2S)].
Additional Material:
2 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bms.1200101208
