The adenosine deaminase of Bacterium cadaveris.

The deamination of adenosine by various tissue preparations was studied by Schmidt in 1928 and later by Klein (1941), and Conway and Cooke (1939). McElroy and Mitchell (1946) demonstrated the presence of the enzyme in Neurospora and in Aspergilli. The enzyme was partially purified by Kalckar (1947) in a series of studies on purine-related enzymes in calf mucosa homogenate. Recent miscellaneous studies have been concerned with the specificity, occurrence, and adaptive formation of the enzyme, principally in animal tissue. In studying the aspartase of Bacterium cadaveris (apparently identical with B. cadaveris ATCC 9760) we became interested in adenosine deammnase because of the stimulating effect of both adenosine and inosine on the deamination of aspartic acid. This effect was observed first by Gale (1938) in an extensive study of bacterial aspartase. He considered the possibility that adenosine deaminase might be directly involved in the deamination of aspartate, inosine functioning as an intermediate ammonia acceptor. Because of the incompatibility of the rates of the two deaminations in whole cells of Escherichia coli, however, Gale concluded that the amination of inosine and the subsequent deamination of the newly formed adenosine were not linked to the deamination of aspartic acid, and that the role of adenosine was probably coenzymatic. The objectives of this study were the prepara-