ADK and heart failure: The AK contribution to total phosphotransfer in the healthy heart is ∼10% (compared to 89% for creatine kinase) (Dzeja et al., 1999) however, in the dog model of pacing-induced heart failure, phospho-transfer via AK increased by 134%, contributing 21% of the total ATP turnover, while phosphotransfer via CK was reduced by 52% (Dzeja et al., 1999).