PURIFICATION AND CHARACTERIZATION OF A TISSUE-SPECIFIC ELONGATION-FACTOR-1-ALPHA (EF-1-ALPHA-2) FROM RABBIT MUSCLE

The peptide elongation factor 1 alpha (EF-1 alpha) has been isolated a nd characterised from a number of species. Recently we and others have reported the existence of an isoform of the ubiquitously expressed EF -1 alpha mRNA in higher eukaryotes, including human cells. This isofor m has a tissue specific expression pattern, confining it primarily to muscle, heart, and brain. In the present study we have purified the is oform of EF-1 alpha from rabbit muscle. Using partial amino acid analy sis, we can conclude that in rabbit muscle essentially only the isofor m of elongation factor 1 alpha, designated EF-1 alpha 2, is translated . Preliminary activity assays show that the isoform has the same funct ional activities as the normal EF-1 alpha, designated EF-1 alpha 1, in relation to protein synthesis, but may behave differently in the abil ity to bind nucleotides. Based on the availability of the isoforms of EF-1 alpha purified from a mammalian species, it will be possible to c onduct further comparative studies in order to elucidate the different functions of EF-1 alpha 1 and EF-1 alpha 2 proteins. (C) 1998 Academi c Press.