A powerful inhibitor of guanine deaminase. 
The synthesis of 9-(p-carbetoxyphenyl) guanine is reported.  The assays carried out on guanine deaminase from rat and rabbit liver and pig brain show that this compound is a powerful inhibitor.  The compound has a Ki = 5 micronM for the enzyme from pig brain.  The use of the inhibitor for the synthesis of a specific adsorbent for guanine deaminase was studied.