CHEMICAL REAGENTS OF POLYPEPTIDES SIDE-CHAIN - RELATIONSHIPS BETWEEN SOLUBILITY PROPERTIES AND ABILITY TO CROSS THE INNER MITOCHONDRIAL-MEMBRANE

The correlation between the solubility properties of DCCD and EDAC (ca rboxyl specific groups reagents) and AI, NBD-Cl and TNM (tyrosyl speci fic reagents) and their efficiency to penetrate through the inner mito chondrial membrane, has been done. The penetration of the reagents was evaluated by using their ability to inactivate D-3-hydroxybutyrate de hydrogenase (EC 1.1.1.30) in its natural location,,i.e. in intact mito chondria, or in its inverted location, i.e. in inside-out submitochond rial vesicles. For DCCD, AI, NBD-Cl and TNM there is a good correlatio n between the phase partition in octanol/water and the ability to cros s or not the inner mitochondrial membrane. In contrast, there is a dis crepancy for EDAC reagent which is hydrophilic, while it significantly inhibits BDH in intact mitochondria. The knowledge of the properties of these reagents can be very useful to locate strategic aminoacid res idues in important biological functions.