Some properties of an extracellular adenosine deaminase produced from Streptomyces sp. Y-225 were examined after 30~80% of ammonium sulfate fractionation. The optimun pH and temperature for the stability of this enzyme were found to be near 7.0
and
40C,
respectively. The enzyme was more stable in 0.05M of potassium phosphate buffer than 0.05M of tris-HCI buffer. As results of examination for the enzyme activity to various pHs, the enzyme was generally highest in its activity near pH 7.0 but
inactivated
completely near pH 4.0 and pH 8.5 The enzyme activity to tempertures was highest near 37℃ and completely disappeared near 60℃. Of metal ions used, 1 mM of Ba2+ increased slightly the enzyme activity, but 1 mM of Ag2+ markedly inactivated the
enzyme
activity. I mm of a, a' -dipyridyl, NaCN and ο-phenanthroline, including 10mMof ethylenediaminetetraacetic acid, monoiodoacetate, pentachlorophenol and p-chloromercuric benzoate completely inhibited the enzyme activity but 0.1mM of NaF, NaN3 and
monoiodoacctate slightly increased the enzyme activity.
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