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Isolation of Eukaryotic Initiation Factor 2 from Rat Brain
Author(s) -
Calés Carmela,
Salinas Matilde,
Fando Juan L.
Publication year - 1985
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1985.tb05557.x
Subject(s) - sodium dodecyl sulfate , chromatography , gtp' , biochemistry , polyacrylamide gel electrophoresis , chemistry , gel electrophoresis , specific activity , microsome , sodium , biology , enzyme , organic chemistry
Eukaryotic initiation factor 2 (eIF‐2) was isolated from salt‐washed microsomes of 4‐day‐old rat brain which show a high rate of protein synthesis. A three‐step purification scheme was employed, including heparin‐Sepharose, phosphocellulose, and DEAE‐cellulose column chromatography. Sodium dodecyl sulfate‐polyacrylamide gel electrophoresis of the isolated factor revealed three polypeptides with molecular weights of 43,000, 54,000, and 59,000 and 90% purity. The rat brain eIF‐2 forms ternary complexes with [ 3 H]methionyl‐tRNA i and GTP. In terms of specific activity, the purification does not correspond to that revealed by electrophoretic analysis. During purification there is an apparent loss of additional factors that modulates the activity of eIF‐2 and explains the high rate of activity of the crude fraction.