Absence of adenosine deaminase activity in a mammalian cell line transformed by Rous sarcoma virus.

No detectable adenosine deaminase activity was found in whole cells or 105,000g cytosol preparations of B-mix K-44/6 cells when either [3H]adenosine or [3H]arabinosyladenine was used as substrate. When grown in tissue culture medium supplemented with horse serum these cells provide a deaminase-free system not requiring the use of an adenosine deaminase inhibitor.