Menu Close

What is the role of shuttle system?

What is the role of shuttle system?

The malate-aspartate shuttle system, also called the malate shuttle, is an essential system used by mitochondria, that allows electrons to move across the impermeable membrane between the cytosol and the mitochondrial matrix. The electrons are created during glycolysis, and are needed for oxidative phosphorylation.

How does shuttle mechanism differ from another?

How do shuttle mechanisms differ from one another? NADH is produced by glycolysis, which occurs in the cytosol, but NADH in the cytosol cannot cross the inner mitochondrial membrane to enter the electron transport chain. However, the electrons can be transferred to a carrier that can cross the membrane.

How many types of shuttle systems are there?

Two types of shuttle mechanisms have the effect of bringing cytosolic reducing equivalents into the matrix, without NADH itself actually entering the matrix. These shuttles are the glycerol phosphate shuttle and the malate/aspartate shuttle.

Which shuttle system is more active in brain?

There is evidence that both the malate-aspartate shuttle and glycerol phosphate shuttle function in brain; however, there is controversy about the relative importance and cellular localization of these shuttles. The malate-aspartate shuttle is considered the most important shuttle in brain.

Why is malate-aspartate shuttle Important?

The malate-aspartate (M-A) shuttle provides an important mechanism to regulate glycolysis and lactate metabolism in the heart by transferring reducing equivalents from cytosol into mitochondria.

Where is the glycerol 3 phosphate shuttle?

The glycerol-3-phosphate shuttle is a pathway that translocates electrons produced during glycolysis across the inner membrane of the mitochondrion for oxidative phosphorylation by oxidizing cytoplasmic NADH to NAD+.

What are the shuttles of etc?


Name In To mitochondrion To ETC
Glycerol phosphate shuttle Glycerol 3-phosphate QH2 (~1.5 ATP)
Malate-aspartate shuttle Malate NADH (~3 ATP)

Where is the malate shuttle?

The malate-aspartate shuttle (sometimes simply the malate shuttle) is a biochemical system for translocating electrons produced during glycolysis across the semipermeable inner membrane of the mitochondrion for oxidative phosphorylation in eukaryotes.

What is oxidative phosphorylation?

Oxidative phosphorylation is the metabolic pathway in which electrons are transferred from electron donors to electron acceptors in redox reactions; this series of reactions releases energy which is used to form ATP.

What is the difference between malate-aspartate shuttle and glycerol phosphate shuttle?

Glycerol-3-phosphate shuttle generates 2 ATP for every cytosolic molecule oxidized, as FADH2 bypasses the first phosphorylation site in the electron transport chain. Malate aspartate shuttle generates 3 ATP for every cytosolic molecule oxidized. So, it is more efficient than the glycerol-3-phosphate shuttle.

Are there any shuttle mechanisms in the brain?

This mechanism has also been observed in mammalian muscle and brain. A more complex and more efficient shuttle mechanism is the malate–aspartateshuttle, which has been found in mammalian kidney, liver, and heart. Thisshuttle uses the fact that malate can cross the mitochondrial membrane, while oxaloacetate cannot.

How are mitochondrial shuttles used in electron transport?

The mitochondrial shuttles are systems used to transport reducing agents across the inner mitochondrial membrane. NADH cannot cross the membrane, but it can reduce another molecule that can cross the membrane, so that its electrons can reach the electron transport chain. The two main systems in humans are:

What kind of metabolites can the shuttle transport?

The shuttles contains a system of mechanisms used to transport metabolites that lack a protein transporter in the membrane, such as oxaloacetate.

How are enzymes and transporters involved in the shuttle process?

Shuttles are systems of enzymes and transporters. The enzymes convert molecules into metabolites that are capable of crossing membranes via the transporters, a process that is frequently followed by reformation of the original molecule.