This protein is one of two protein components of a 42S RNP particle that is very abundant in previtellogenic oocytes. A major function served by 42sp50 appears to be the storage of tRNAs for later use in oogenesis and early embryogenesis. Purified 42S particles can directly transfer aminoacyl tRNA to ribosomes. The 42S RNP particle comprises four subunits each of which contains one molecule of 5S RNA, three molecules of tRNA, two molecules of EF1-alpha and one molecule of the 5S RNA binding protein 43. 3 EF-1-alpha are expressed under different developmental control in Xenopus laevis. This protein is expressed exclusively in immature oocytes. Belongs to the TRAFAC class translation factor GTPase superfamily. Classic translation factor GTPase family. EF-Tu/EF-1A subfamily.