ATP Synthase

The energy stored in the hydrogen ion gradient can be used to drive the synthesis of ATP from ADP and inorganic phosphate. The conversion is accomplished by a marvelous nanoma-chine called ATP synthase. At its most basic, the operation is a simple one and is summarized in Figure 12.9. Once again, the circle symbolizes the linkage between the enzyme and carrier functions. ATP synthase is a protein complex that is also known as mitochondrial ATPase because it can carry out the reverse reaction,...

Reduced Nicotinamide Adenine Dinucleotide NADH

This, the most energy rich of the four currencies, is shown in Figure 12.1a. NADH is a strong reducing agent. It will readily react to allow two hydrogen atoms to be added to molecules, in the general reaction NADH H X NAD H2X. NAD is shown in Figure 12.1b. Addition of hydrogen atoms to molecules, or the removal of oxygen atoms, is called reduction. The opposite of reduction is oxidation, the addition of oxygen. Because oxygen atoms tend to take more than their fair share of electrons in any...

Adpatp Exchanger

ATP synthase makes ATP inside the mitochondrion. For the ATP to be available to the rest of the cell, there needs to be a mechanism to enable it to leave the mitochondrion for use in the cytosol. This job is performed by another carrier, the ADP ATP exchanger. This protein has no enzymatic action it simply moves ADP in one direction across the mitochondrial inner membrane and ATP in the opposite direction. In most eukaryotic cells the carrier operates in the direction shown in Figure 12.3....