Mechanism of action of carbonyl compounds (4-hydroxyalkenals) derived from the peroxidation of hepatic microsomal lipids [Sul meccanismo di azione dei composti carbolinici (4-idrossialchenali) derivati dalla perossidazione dei lipidi microsomali epatici]

When carbonyl compounds released during the NADPH-Fe dependent peroxidation of liver microsomal lipids and identified as 4-hydroxyalkenals (almost entirely 4-hydroxynonenal) are incubated with liver microsomes, a substantial amount of these products can be recovered bound to the microsomal protein, by allowing the microsomal protein to react with 2,4-dinitrophenyl-hydrazine. Concomitantly with the binding, a decrease in the 'exposed' and total -SH groups of the microsomal protein occurs. The decrease in the total -SH groups is stechiometrically accounted for by the amount of carbonyl compounds bound to the microsomal protein. Still in concomitance with the binding, the G-6-Pase activity of the microsomes markedly decreased. Therefore a mechanism similar to that described for the binding of 4-hydroxyalkenals to -SH groups of protein and enzymes can be postulated.