Catalyzes the hydrolysis of GTP bound to the 40S ribosomal initiation complex (40S.mRNA.Met-tRNA[F].eIF-2.GTP) with the subsequent joining of a 60S ribosomal subunit resulting in the release of eIF-2 and the guanine nucleotide. The subsequent joining of a 60S ribosomal subunit results in the formation of a functional 80S initiation complex (80S.mRNA.Met-tRNA[F]). eIF-5 is essential for cell viability. Monomer. Interacts with NIP1 and SUI3. The factors eIF-1, eIF-2, eIF-3, TIF5/eIF-5 and methionyl-tRNAi form a multifactor complex (MFC) that may bind to the 40S ribosome. TIF32, NIP1 and TIF5/eIF-5 comprise a minimal 40S-ribosome-binding unit. Present with 48300 molecules/cell in log phase SD medium. Produced by alternative initiation at Met-18 of isoform Long. Belongs to the eIF-2-beta/eIF-5 family.