Effects of different concentrations of metal ions on degradation of adenosine triphosphate in common carp (Cyprinus carpio) fillets stored at 4 °C: An in vivo study

The impact of different concentrations of Na+, K+, Ca2+, Mg2+, Fe2+, and Zn2+ on the degradation of adenosine triphosphate (ATP) and the influence of these ions on the activity of adenosine monophosphate deaminase (AMP-deaminase) and acid phosphatase (ACP) in common carp fillets (in vivo) during 4 °C storage was examined. The content of ATP, inosine monophosphate (IMP), and hypoxanthine (Hx), and the activity of AMP-deaminase and ACP were determined. Results indicated that the effects of different concentrations of six kinds of metal ions on AMP-deaminase and ACP were not the same. Na+, K+, Fe2+, and Zn2+ enhanced AMP-deaminase activity, which led to the rapid degradation of ATP and to the generation of a large quantity of IMP within a short time. Ca2+ and Mg2+ delayed the change in AMP-deaminase and ACP activity in carp and caused a further delay in the degradation of ATP. Fe2+ and Zn2+ inhibited ACP activity, which reduced the decomposition of IMP and the formation of Hx.