Multiple selenocysteine content of selenoprotein P in rats.
Partially purified selenoprotein P from rat plasma was digested with either trypsin, endoprotease Lys-C, or endoprotease Arg-C and analyzed by high pressure liquid chromatography and sodium dodecyl sulfate polyacrylamide gel electrophoresis. Several 75Se-labeled peptides were detected. The moles of selenium in selenoprotein P were estimated based on the 75Se content of the 75Se-labeled peptide fragments. Using this method, selenoprotein P was shown to contain approximately 9 moles of selenium. This is the first report of a selenoprotein containing more than one selenium per polypeptide. These findings support the proposed function of this protein in selenium transport.
Motchnik
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PA
Department of Food Science and Technology, University of California, Davis 95616.
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D000818:Animals; D002851:Chromatography, High Pressure Liquid; D003545:Cysteine / Q000031:analogs & derivatives* / Q000032:analysis; D004591:Electrophoresis, Polyacrylamide Gel; D010450:Endopeptidases; D008666:Metalloendopeptidases; D010446:Peptide Fragments / Q000032:analysis; D011506:Proteins / Q000032:analysis*; D051381:Rats; D012643:Selenium / Q000032:analysis*; D017279:Selenocysteine; D051149:Selenoprotein P; D051140:Selenoproteins; D012697:Serine Endopeptidases; D014357:Trypsin
D010446:Peptide Fragments; D011506:Proteins; D051149:Selenoprotein P; D051140:Selenoproteins; D017279:Selenocysteine; D010450:Endopeptidases; C044499:submandibular proteinase A; D012697:Serine Endopeptidases; D014357:Trypsin; D008666:Metalloendopeptidases; C039830:peptidyl-Lys metalloendopeptidase; D012643:Selenium; D003545:Cysteine