Purification and properties of double-stranded RNA-specific adenosine deaminase from calf thymus.

摘要: A double-stranded RNA-specific adenosine deaminase, which converts to inosine, has been purified homogeneity from calf thymus. The enzyme was approximately 340,000-fold by a series of column chromatography steps. consists single polypeptide with molecular mass 116 kDa as determined electrophoresis on SDS/polyacrylamide gel. native protein sediments at 4.2 s in glycerol gradients and Stokes radius 42 upon gel-filtration chromatography. This leads an estimate 74,100 for the weight, suggesting that exists monomer solution. Enzyme activity is optimal 0.1 M KCl 37 degrees C. Divalent metal ions or ATP not required activity. Km RNA substrate 7 x 10(-11) M. Vmax 10(-9) mol inosine produced per min mg Kcat 0.13 min-1.