Search

We present data on values of adenosine deaminase (ADA) activity in bovine fetus and calf thymus. Between 13 and 17 weeks of fetal life enzyme activity in thymus increases up to levels observed in older fetuses and calf. ADA activity of thymus is characterized by the presence of three enzymic form ("A", "B", "C") which show molecular weights of greater than 1 x 10(6), 310,000 and 55,000, respectively. Forms "B" and "C" were compared. The relative amounts of the three forms in 17 weeks old fetus were quite similar to those observed in calf thymus.

It has been observed that adenosine deaminase activity in human beings differ between serum and tissues reference to optimal pH, Km and relative substrate specificity. Based upon the ratio between the activity of deaminase on 2'deoxyadenosine and adenosine, we may distinguish between a "serum type" enzyme and a "tissue type" enzyme. In sample of pleural and peritoneal fluid extracted from 92 patients with variable pathology, we have found the existence of a "tissue type" enzyme in three patients having empyemic pleural effusions and ten with malignant systemic pathology.