
Adenosine deaminase (ADA) is an enzyme which involves in purine metabolism and catabolism of adenosine and deoxyadenosine into inosine and deoxyinosine. There are three isoenzymes; ADA1 and ADA2, ADA1+cp. Total ADA is very important in the tumor cell growth. In the present study the activities of ADA, its isoenzymes (ADA1 and ADA2) have been examined in the serum ovarian tumors of 30 patients and 30 normal serums. with autoanalyzer HITACHI 912 byspectrophotometry method by or presence or absence of erythro-9-2-hydroxy-3-nonyl Adenosine (EHNA). We found the mean values for tADA، ADA2 and ADA1 in healthy controls 14.35 U/L and 8.44 U/L and 5.91 U/L respectively and in Ovarian patients 29.56 U/Land 19.23 U/L and 10.39 U/L respectively. When compared to the healthy controls, serum total ADA and ADA1 and ADA2 levels were significantly higher (P<0.001) in Ovarian cancer patients.it, can be proposed that when we compared to the healthy controls serum total ADA and ADA1 and ADA2 levels with ovarian cancer patients like other Parameters of disease activity like tumor marker CA-125, it could be diagnostic value of the Pathophysiology. Also in this research molecular weight of ADA Isoenzymes was investigated ADA1=35KD and ADA2=110KD.