Involved in the beta-oxidation of the cholesterol side chain (PubMed:19822655). It is important for utilization of cholesterol as a sole carbon source in vitro and for full virulence in the chronic stage of mouse lung infection (PubMed:19822655). Catalyzes the thiolysis of 3,22-dioxochol-4-en-24-oyl-CoA to yield 3-oxo-4-pregnene-20-carboxyl-CoA (3-OPC-CoA) and acetyl-CoA (PubMed:25482540). Also able to use acetoacetyl-CoA (AcAcCoA) as substrate (PubMed:19822655). acetyl-CoA + an acyl-CoA = a 3-oxoacyl-CoA + CoA 3-oxochol-4-en-22-oyl-CoA + acetyl-CoA = 3,22-dioxochol-4-en-24-oyl-CoA + CoA kcat is 0.725 sec(-1) for 3,22-dioxochol-4-en-24-oyl-CoA substrate (PubMed:25482540). kcat is 0.076 sec(-1) for AcAcCoA substrate (PubMed:19822655). kcat is 0.018 sec(-1) for CoA substrate (PubMed:19822655). Steroid metabolism; cholesterol degradation. Dimer of dimers. Induced by cholesterol and repressed by KstR. Cells lacking this gene display an attenuated disease phenotype with reduced colony-forming units in comparison to the wild-type. This mutant is unable to metabolize cholesterol to androst-4-ene-3,17-dione (AD) and androsta-1,4-diene-3,17-dione (ADD). Belongs to the thiolase-like superfamily. Thiolase family.