QSAR for phospholipase A2 inhibitions by 1-acyloxy-3-N-n-octylcarbamyl-benzenes.
1-Acyloxy-3-N-n-octylcarbamyl-benzenes are potent reversible competitive inhibitors of Naja mocambique mocambique phospholipase A2 with the Ki values from 9.6 to 119 microM. The pKi values are correlated to both Taft substituent constant sigma* and Hansch hydrophobicity constant pi. The pre-steady state inhibition studies indicate that the pK(S) values for the first inhibition step are linearly correlated to sigma* alone with the rho* of -0.09 for this correlation. Thus, the first inhibition step may involve the insertion of the inhibitor to hepta-coordinated Ca2+ ion of the enzyme to form the octa-coordinated Ca2+ ion of the enzyme. The log(k2/k(-2)) values for the second inhibition step are linearly correlated to pi alone, and the psi value for this correlation is 0.13. Therefore, the second step inhibition step may involve the van der Waals' interaction between the acyl group of the inhibitor and Tyr 69 of the enzyme.
Lin
Gialih
G
Department of Chemistry, National Chung-Hsing University, Taichung 402, Taiwan. glin@dragon.nchu.edu.tw
Yu
Gia-Yun
GY
D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D001555:Benzene Derivatives / Q000138:chemical synthesis* / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000138:chemical synthesis / Q000494:pharmacology; D007700:Kinetics; D015394:Molecular Structure; D010741:Phospholipases A / Q000037:antagonists & inhibitors*; D054467:Phospholipases A2; D021281:Quantitative Structure-Activity Relationship
D000894:Anti-Inflammatory Agents, Non-Steroidal; D001555:Benzene Derivatives; D004791:Enzyme Inhibitors; D010741:Phospholipases A; D054467:Phospholipases A2