Investigations into the Origin of the Molecular Recognition of Several Adenosine Deaminase Inhibitors
作者:Irina Gillerman、Bilha Fischer
DOI:10.1021/jm101286g
日期:2011.1.13
Inhibitors of adenosine deaminase (ADA, EC 3 5 4 4) are potential therapeutic agents for the treatment of various health disorders Several highly potent inhibitors were previously identified, yet they exhibit unacceptable toxicities We performed a SAR study involving a series of C2 or C8 substituted purine-riboside analogues with a view to discover less potent inhibitors with a lesser toxicity We found that any substitution at C8 position of nebularine resulted in total loss of activity toward calf intestinal ADA However several 2-substituted-adenosine, 8-aza-adenosine, and nebularine analogues exhibited inhibitory activity Specifically, 2-Cl-purine riboside, 8-aza-2-thiohexyl adenosine, 2-thiohexyl adenosine, and 2-MeS-purine riboside were found to be competitive inhibitors of ADA with K-i values of 25, 22, 6, and 3 mu M, respectively We concluded that electronic parameters are not major recognition determinants of ADA but rather steric parameters A C2 substituent which fits ADA hydrophobic pocket and improves H-bonding with the enzyme makes a good inhibitor In addition, a gg rotamer about C4'-C5' bond is apparently an important recognition determinant