Tightly coupled inside-out vesicles were prepared from Paracoccus denitrificanscells (SPP, sub-Paracoccusparticles) and characterized kinetically. The rate of NADHoxidation, catalysed by SPP, increases 6–8 times on addition of gram-icidin. The vesicles are capable of catalysing DlH + -dependent reverse electron transfer fromquinol toNAD + . The kinetic parameters of the NADH-oxidase and the reverse electron transfer carried out by membrane-bound P. denitrificanscomplex I were estimated and compared with those of the mitochondrial enzyme. .
