A small protein (arrest peptide) encoded upstream of inducible ornithine carboxylase gene (speF) that controls expression of downstream genes (usually speF and potE) by transcriptional and translational attenuation. 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. Belongs to the speF operon leader peptide family.