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 one large insertion sequence (IS1) that divides the clpP gene into two sequence domains. The insertion sequence forms a continuous open reading frame with its upstream and downstream sequence domains. Belongs to the peptidase S14 family.