the increased expression of only one of the two functional ada alleles , the requirement for a stepwise selection protocol to obtain cells with increased adenosine deaminase , and the instability of the adenosine deaminase phenotype in the absence of selective pressure suggest that the alteration of adenosine deaminase phenotype in the drug-resistant cells was the result of adenosine deaminase gene amplification .
C0001457
adenosine deaminase
C1412179
adenosine deaminase gene