AMP-deaminase was purified to electrophoretic homogeneity from white skeletal muscle of a teleost fish, the common carp, Cyprinus carpio. The purified enzyme was highly stable and showed non-Michaelis-Menten kinetics with a S0.5 value for AMP of 2.52 ± 0.16 mM (SEM) and a Hill coefficient of 1.19 ± 0.11. Specific activity of the purified enzyme was 1000-1200 U/mg protein. The pH optimum was 6.3 and the enzyme was activated by ADP and ATP, but inhibited by phosphate and fluoride. Low concentrations of NaCl and KCl (100-150 mM) activated, whereas higher concentrations were inhibitory. Free radicals inactivated the enzyme, decreasing Vmax by one-half but not affecting S0.5 or Hill coefficient. Possible regulatory mechanisms of AMP-deaminase activity in fish muscle are discussed.

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Keywords AMP-deaminase, Cyprinus carpio, Kinetics, Purification
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Journal Comparative Biochemistry and Physiology - B Biochemistry and Molecular Biology
Lushchak, V.I. (Volodymyr I.), Husak, V.V. (Viktor V.), & Storey, K. (2008). Regulation of A{cyrillic}M{cyrillic}R{cyrillic}-deaminase activity from white muscle of common carp Cyprinus carpio. Comparative Biochemistry and Physiology - B Biochemistry and Molecular Biology, 149(2), 362–369. doi:10.1016/j.cbpb.2007.10.008