Isolation and characterization of adenosine nucleosidase from yellow lupin(Lupinus luteus)

Adenosine nucleosidase from yellow lupin (Lupinus luteus) seeds has been pu rified to homogeneity. The enzyme catalyzes the hydrolysis of purine nucleo sides to the base and the sugar. The enzyme was purified 146-fold to yield a specific activity of 6.6 mu mol/min mg. The best substrate was 5'-deoxyad enosine followed by adenosine, 2'-deoxyadenosine, and guanosine. Protonatio n of N7 appears to be a requirement for reaction as tubercidin (7-deazaaden osine) is not a substrate. The 3'-hydroxyl group is also extremely importan t for catalysis as evidenced by the low substrate activity for cordycepin ( 3'-deoxyadenosine). The enzyme exists as a dimer with a native molecular we ight of 72 000. (C) 2000 Published by Elsevier Science Ireland Ltd. All rig hts reserved.