ketolysis is the process of circulating ketone bodies in tissue is broken down to form acetyl-coA. This product is then used for further oxidative phosphorylation by entering the citric acid cycle (krebs cycle) to yield reducing equivalents (NADH) which releases stored energy.
Opposing ketolysis is ketogenesis, which is the synthesis of ketone bodies. Some tissues (like vertebrae brain and shark muscle) cannot metabolize fatty acids (i.e. acetyl coA) so they convert the acetyl coA into ketobe bodiess to circulate