IDENTIFICATION OF CATALYTIC SITE OF RAT-LIVER GLUTATHIONE PEROXIDASE AS SELENOCYSTEINE
IDENTIFICATION OF CATALYTIC SITE OF RAT-LIVER GLUTATHIONE PEROXIDASE AS SELENOCYSTEINE
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DOI：
10.1021/bi00606a028
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发表时间：
1978-01-01
期刊：
影响因子：
2.9
通讯作者：
TAPPEL, AL
中科院分区：
文献类型：
--
作者：
FORSTROM, JW;ZAKOWSKI, JJ;TAPPEL, AL
A procedure was developed to isolate 75Se-labeled rat liver glutathione peroxidase (glutathione:H2O2 oxidoreductase, EC 1.11.1.9) at 30-50% purity with 20-30% yields in 4-5 days. Using these preparations of glutathione peroxidase, the Se moiety in the enzyme was identified as selenocysteine by derivatizing the seleno group with either iodoacetate or ethylenimine in the intact protein, hydrolyzing the protein with 6 N HCl, and cochromatographing the 75Se-labeled products with known standards. Techniques employed were anion-exchange chromatography, cation-exchange chromatography, gel-permeation chromatography, 2-dimensional TLC and automated amino acid analysis. The selenocysteine moiety was identified as the catalytic site in glutathione peroxidase by specifically labeling the enzyme with [14C]iodoacetate on the 75Se-labeled Se atom and fractionating the 14C, 75Se-labeled derivative after acid hydrolysis. The reduced form of glutathione peroxidase apparently contains the selenocysteine selenol (-SeH) at the catalytic site.
