The relevance of the non-canonical PTS1 of peroxisomal catalase

► Peroxisomal catalases contain non-canonical peroxisomal sorting 1 sequences (PTS1). ► The catalase PTS1 has reduced affinity for Pex5 relative to -SKL. ► The catalase PTS1 results in prolonged residence times in the cytosol. ► Replacing ‐SKI by ‐SKL results in reduced catalase enzyme activity in vivo. ► Replacing ‐SKI by ‐SKL results in accumulation of catalase aggregates in peroxisomes.