Utilization of Selenocysteine by a Cysteinyl-tRNA Synthetase from Phaseolus aureus.
An l-cysteinyl-tRNA synthetase (EC 6.1.1.16) from Phaseolus aureus has been purified approximately 200-fold. The enzyme uses selenocysteine as substrate in the ATP-PPi exchange assay; other cysteine analogs were inactive. The molecular weight as determined by Sephadex G-200 column chromatography is about 61,000; sodium dodecyl sulfate and 8 m urea acrylamide gel electrophoresis indicate that the enzyme is a dimer consisting of two identical monomers of molecular weight 30,000. A method for the preparation of selenocysteine from selenocystine is described.
Shrift
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A
Department of Biological Sciences, State University of New York, Binghamton, New York 13901.
Bechard
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D
Harcup
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C