Functions in the N-end rule pathway of protein degradation where it conjugates Leu, Phe and, less efficiently, Met from aminoacyl-tRNAs to the N-termini of proteins containing an N-terminal arginine or lysine. L-leucyl-tRNA(Leu) + N-terminal L-lysyl-[protein] = H(+) + N-terminal L-leucyl-L-lysyl-[protein] + tRNA(Leu) L-leucyl-tRNA(Leu) + N-terminal L-arginyl-[protein] = H(+) + N-terminal L-leucyl-L-arginyl-[protein] + tRNA(Leu) an N-terminal L-alpha-aminoacyl-[protein] + L-phenylalanyl-tRNA(Phe) = an N-terminal L-phenylalanyl-L-alpha-aminoacyl-[protein] + tRNA(Phe) Monomer. Belongs to the L/F-transferase family.