JBC, Vol. 250, Issue 19, 7541-7546, Oct, 1975
Nicotinamide adenine dinucleotide glycohydrolase from rat liver nuclei. Isolation and characterization of a new enzyme
K. Ueda, M. Fukushima, H. Okayama and O. Hayaishi
A new type of nicotinamide adenine dinucleotide glycohydrolase (NADase) has
been isolated from rat liver nuclei. When partially purified chromatin is
passed through a Sephadex G-200 column in the presence of 1 M NaCl, enzyme
activities catalyzing the liberation of nicotinamide from NAD elute in two
peaks. One, which appears in the void volume fraction, hydrolyzes the
nicotinamide-ribose linkage of NAD to produce nicotinamide and ADP-ribose
in stoichiometric amounts. This activity is not inhibited by 5 mM
nicotinamide. The other, which elutes much later, catalyzes the formation
of poly(ADP-ribose) from NAD and is completely inhibited by 5 mM
nicotinamide. The former, NADase, is DNase-insensitive and thermostable,
has a pH optimum of 6.5 to 7, a Km for NAD of 28 muM, and a Ki for
nicotinamide of 80 mM, and hydrolyzes NADP as well as NAD. The latter,
poly(ADP-ribose) synthetase, is sensitive to DNase treatment and heat
labile, has a pH optimum of 8 to 8.5, a Km for NAD of 250 muM and a Ki for
nicotinamide of 0.5 mM and is strictly specific for NAD. Further, the
former NADase is shown to lack transglycosidase activity, which has been
documented to be a general property of NADases derived from animal tissues.
These results indicate that the NAD-hydrolyzing enzyme newly isolated from
nuclei is a novel type of mammalian NADase which catalyzes the hydrolytic
cleavage of the nicotinamide-ribose linkage of NAD.