Synthetic inhibitors of serine proteinases. 13. Quantitative structure-activity relationship for inhibition of trypsin and thrombin by 4-amidinophenyl compounds with a ketone structure
Stürzebecher, J.; Markwardt, F.; Wagner, G.; Walsmann, P.
Acta Biologica et Medica Germanica 35(12): 1665-1676
1976
ISSN/ISBN: 0001-5318 PMID: 141858 Document Number: 108970
To establish quantitative structure-activity relationships for the inhibition of trypsin, plasmin and thrombin by 4-amidinophenyl compounds with a keto group, attempts have been made to detect correlations between data on inhibition and substituent constants. The inhibitor activity of the derivatives is described by lipophilic or steric substituent constants using linear free energy relationships. To describe the action of beta-ketones, an additional sigma I term is necessary. The lipophilic or steric term stands for binding of the inhibitor side chain to a second hydrophobic binding site of the enzyme. The electronic term describing inductive influences on the keto group suggests the contribution of the beta-keto group to the enzyme inhibitor binding via a tetrahedral conformation of the carbonyl carbon.