Purification and Characterization of Extracellular Adenosine Deaminase from a Streptomyces sp.

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Extracellular adenosine deaminase(adenosine aminohydrolase, EC3.5.4.4)was purified from the culture filtrate of Streptomyces sp. J-845S by ammonium sulfate precipitation and column chromatography on DEAE-cellulose, DEAE-Sephadex A-50,Sephadex G-100,and CM-cellulose. The purified enzyme preparation was homogeneous by the criterion of polyacrylamide gel electrophoresis. The molecular weight of the emzyme was estimated to be about 90,000 by gel filtration with Sephadex G-100 and about 45,000 by SDS-polyacryl-amide gel electrophoresis, suggesting that the enzyme consisted of two subunits, and its isoelectric point was 7.8. The enzyme was stable at pH 3.5-5.5,the optimum pH for the reaction was 5.0-6.0,and the optimum temperature was 55℃ in the optimum pH range. Adenosine, 2'-deozyadenosine, 2', 3'-isopropylidene adenosine, AMP, adenosine-3'-monophosphate, and cAMP were substrates of the enzyme, and the K_m values for these compounds were 0.67,0.22,0.29,0.17,2.0,and 0.5mM, respectively. The enzyme reaction was promoted by Fe^<3+>, and inhibites by Hg^<2+>, Ag^+, and o-phenanthroline.
公益社団法人日本生物工学会の論文
1991-01-25