A small protein (arrest peptide) encoded upstream of inducible ornithine carboxylase gene (speF) that controls expression of downstream genes (speF and potE) by transcriptional and translational attenuation. Its expression controls transcription and translation of downstream SpeF; translation pausing at low Arg levels on this mRNA prevents premature Rho-dependent transcription termination of speF and also enhances SprF translation by preventing sequestration of its ribosome-binding site. In the presence of high Arg levels translation of this protein allows the formation of an speF mRNA structure that is degraded by RNase G. Binds ornithine in stalled 70S ribosomes, blocking the upper two-thirds of the exit tunnel. Contacts 23S rRNA and ribosomal proteins L4 and L22. Induced by ornithine, repressed by putrescine. Part of the speFL-speF-potE operon. Replacing its start codon by AAA (Lys) prevents expression of SpeFL and leads to generation of a prematurely truncated speF transcript, and thus prevents expression of downstream SpeF. Belongs to the speF operon leader peptide family.