Cleaves peptides in various proteins in a process that requires ATP hydrolysis. Has a chymotrypsin-like activity. Plays a major role in the degradation of misfolded proteins (By similarity). Hydrolysis of proteins to small peptides in the presence of ATP and magnesium. alpha-casein is the usual test substrate. In the absence of ATP, only oligopeptides shorter than five residues are hydrolyzed (such as succinyl-Leu-Tyr-|-NHMec, and Leu-Tyr-Leu-|-Tyr-Trp, in which cleavage of the -Tyr-|-Leu- and -Tyr-|-Trp bonds also occurs). Component of the chloroplastic Clp protease core complex. This gene contains two large insertion sequences (IS1 and Ceu clpP intein) that divide the clpP gene into three sequence domains. Each insertion sequence forms a continuous open reading frame with its upstream and downstream sequence domains. This protein undergoes a protein self splicing that involves a post-translational excision of the intervening region (intein) followed by peptide ligation. Belongs to the peptidase S14 family.