1971 Volume 69 Issue 2 Pages 317-324
1) The participation of cytochrome b5 in the mierosomal NADH-cytochrome c reductase activity was kinetically studied. Most of the activity could be ascribed to the action of cytochrome b5.
2) Steady-state kinetics of the NADH-cytochrome c reductase activity of intact microsomes has revealed that the enzyme follows a so-called ping-pong mechanism. This is also true for the mechanism of NADH-linked reduction of solubilized cytochrome b5, when catalyzed by intact microsomes.
3) The non-ionic detergent, Emalgen 810, has been used for the study of the mierosomal cytochrome b5 system. The detergent inhibits the reduction of mierosomal bound cytochrome b5, as well as the NADH-cytochrome c reductase activity of microsomes. In contrast, the detergent accelerates the NADH- “soluble” cytochrome b5 reductase activity of microsomes.
4) Liver microsomes, when treated with the detergent, exhibit an enzymic activity for the reduction of metmyoglobin or methemoglobin by NADH.