VIEW ARTICLE    DOI: 10.1094/ASBCJ-44-0086

Nucleic Acid Degrading Enzymes of Barley Malt. III. Adenosine Nucleosidase from Malted Barley. W. J. Lee and R. E. Pyler, Department of Cereal Science and Food Technology, and A. E. Oleson, Department of Biochemistry, North Dakota State University, Fargo 58105. J. Am. Soc. Brew. Chem. 44:0086, 1986.

Adenosine nucleosidase, an enzyme that catalyzes the hydrolytic cleavage of adenosine to adenine and ribose, was examined in malted barley. The enzyme was purified by precipitation with ammonium sulfate, and by column chromatography with diethylaminoethyl (DEAE)-Sephadex, Sephadex G-200, and hydroxylapatite. The enzyme was specific for adenosine and 2'-deoxyadenosine and had no discernable effect on other naturally occurring nucleosides. The molecular weight of the enzyme was approximately 120,000. The optimum pH was about the K_m value for adenosine was 0.27 mM. Adenosine nucleosidase showed no metal ion requirement for optimum activity and was inhibited by Zn²⁺, Cu²⁺, and Hg²⁺ ions. The enzyme in solution was completely inactivated after 15 min at 60° C.

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