Mechanism of biochemical action of substituted 4-methylcoumarins. Part 11: Comparison of the specificities of acetoxy derivatives of 4-methylcoumarin and 4-phenylcoumarin to acetoxycoumarins: protein transacetylase.

摘要: Abstract Our earlier observations led to the identification of a microsomal enzyme termed as acetoxy drug: protein transacetylase (TAase) catalyzing transfer acetyl groups from acetylated polyphenols receptor proteins. TAase was conveniently assayed by irreversible inhibition cytosolic glutathione S-transferase (GST) model acetoxycoumarin, 7,8-diacetoxy-4-methylcoumarin (1). The specificities group on benzenoid ring and position pyran carbonyl coumarin with respect oxygen heteroatom for catalytic activity were also reported earlier. In this communication, we have demonstrated that coumarins dihydrocoumarins having methyl instead phenyl at C-4, when used substrates, resulted in enhancement activity, while saturation double bond C-3 C-4 had no effect activity. A comparison optimized structures 1 7,8-diacetoxy-4-phenylcoumarin (2) suggested observed influence may be due out plane configuration C-4. Further, TAase-catalyzed activation NADPH cytochrome c reductase aflatoxin B1 (AFB1)–DNA binding 4-phenylcoumarins significantly lower compared those caused 4-methylcoumarins.