Substrate specificity of ADPRibase-Mn enzymes.

KM and kcat/KM values for zebrafish wild-type and mutant enzyme are shown as means±S.D. (n = 3–6), and kcat values are derived from them. aNeither the zebrafish wild type nor the rat enzyme display significant activity towards ADP-glucose, UDP-glucose, CDP-glucose, CDP, CMP, AMP or 3′,5′-cAMP. bData taken from [11], [12]. cThe kinetic parameters of 2′,3′-cAMP hydrolysis correspond to the total activity, including the 3′-AMP-forming hydrolysis of the P-O2′ and the 2′-AMP-forming hydrolysis of the P-O3′ linkage. However, given the strong predominance of the P-O2′ linkage hydrolysis, the parameters may be reasonable approximations to this reaction kinetics. dEstimated from the potency of (competitive) inhibition of ADP-ribose hydrolysis by cADPR. end, not determined.