Enzymic synthesis of selenocysteine in rat liver
- 21 July 1981
- journal article
- research article
- Published by American Chemical Society (ACS) in Biochemistry
- Vol. 20 (15) , 4492-4496
- https://doi.org/10.1021/bi00518a039
Abstract
Selenocysteine (2-amino-3-hydroselenopropionic acid) synthesis with cystathionine .beta.-synthase (EC 4.2.1.22) and cystathionine .gamma.-lyase (EC 4.4.1.1) of rat liver was investigated. When selenohomocysteine and serine were incubated with cystathionine .beta.-synthase, selenocystathionine was formed at a rate of 69% of that of cystathionine synthesis. Cystathionine .gamma.-lyase catalyzed .alpha., .gamma. elimination of selenocystathionine to yield .alpha.-ketobutyrate, selenocysteine and NH3. The reaction rate was about 3 times higher than that of cystathionine elimination. Cystathionine .beta.-synthase did not catalyze direct formation of selenocysteine from serine and H2Se. Thus, selenocysteine is synthesized from selenohomocysteine and serine through selenocystathionine by coupling of cystathionine .beta.-synthase and cystathionine .gamma.-lyase reactions. This synthetic pathway was confirmed with a mixture of both enzymes and with a homogenate of rat liver.This publication has 10 references indexed in Scilit:
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