Responsible for the thiolytic cleavage of straight chain 3-keto fatty acyl-CoAs (3-oxoacyl-CoAs) (Probable). Plays an important role in fatty acid peroxisomal beta-oxidation (Probable). Catalyzes the cleavage of short, medium, long, and very long straight chain 3-oxoacyl-CoAs (Probable). acetyl-CoA + an acyl-CoA = a 3-oxoacyl-CoA + CoA 2 acetyl-CoA = acetoacetyl-CoA + CoA acetyl-CoA + tetradecanoyl-CoA = 3-oxohexadecanoyl-CoA + CoA acetyl-CoA + hexanoyl-CoA = 3-oxooctanoyl-CoA + CoA 3-oxohexadecanedioyl-CoA + CoA = acetyl-CoA + tetradecanedioyl-CoA 3-oxo-(6Z,9Z,12Z,15Z,18Z,21Z)-tetracosahexaenoyl-CoA + CoA = (4Z,7Z,10Z,13Z,16Z,19Z)-docosahexaenoyl-CoA + acetyl-CoA Lipid metabolism; peroxisomal fatty acid beta-oxidation. Homodimer. Peroxisomal thiolase is markedly induced (at the level of transcription) by various hypolipidemic compounds in parallel with the other two enzymes of the peroxisomal beta-oxidation system. Belongs to the thiolase-like superfamily. Thiolase family.