Abstract
To clarify the relationship between the substrate structure and enzyme activity, substrate specificity of ATP deaminase from Microsporum audouini was examined in detail, in using 35 kinds of adenine compounds. 5′-ATP, 5′-ATPP, 5′-ADP, 5′-Ad-sulfate, 5′-ADP-ribose, 5′-AMP and 5′-ADP-glucose were rapidly deaminated in this order. Adenosine was deaminated at a slow rate, but adenine was not deaminated. This enzyme also catalyzed the deamination of 3-iso-AMP and the dechlorination of 6-chloropurine riboside. The C′-1 or C′-2 position of ribose is necessary for binding to the enzyme, and the negatively charged group such as phosphate or sulfate at the 5′-position of ribose is most essential for the effective deamination. A probable schematic model showing the relationship between this enzyme and substrate was presented.
