COMPARATIVE STUDIES OF MAMMALIAN ADENOSINE DEAMINASES - SOME DISTINCTIVE PROPERTIES IN HIGHER MAMMALS

1. 1. The pattern of adenosine deaminases in beed liver is very strikingly different from that in lower vertebrates, i.e. chicken, opossum and amphibians. There is no type-B adenosine deaminase in beef liver and the high-molecular-weight enzyme present (type A) can be dissociated into the monomeric type-C enzyme in the presence of high concentrations of ammonium sulfate or sucrose. 2. 2. A survey of hepatic adenosine deaminases in fourteen species of higher mammals including representatives from seven different orders has shown that there are characteristic patterns for the various orders even though they are all distinctive from lower forms in the same way as is beef liver. Carnivores and rodents have predominantly monomeric enzyme whereas rabbits have predominantly polymeric adenosine deaminase. 3. 3. Marsupials (if the opossum is a typical example) have patterns very similar to the chicken and amphibians, i.e. a type-B enzyme is present with a low relative substrate specificity. 4. 4. The pattern of adenosine deaminases in beef liver is strikingly different from the patterns in the heart, spleen and duodenum of the same organism. In the latter tissues there is almost no polymeric enzyme. © 1969.