Malate shuttle is important in
Most of the guides have given glycolysis as the answer. According to me, which is incorrect.
The most important function of malate shuttle is to transport cytosolic reducing equivalents (generated in glycolysis) into the mitochondria.
But, malate shuttle has no direct role in the occurrence of any reaction of glycolysis, i.e. malate shuttle does not take part in the glycolytic process itself. Its role is to generate ATP by transporting NADH into the mitochondria.
You can easily understand this by the fact that anaerobic glycolysis occurs without any participation of the malate shuttle. Hence, presence or absence of malate shuttle has no direct effect on the glycolytic process itself.
On the other hand, the malate shuttle is directly involved in gluconeogenesis by transporting malate out of the mitochondria into the cytosol. Thus without malate shuttle, gluconeogenesis cannot occur.
Thus, malate shuttle is a part of the gluconeogenic process while it is not a part of the glycolytic process.
In short
Most important function of malate shuttle is to transport the reducing equivalents (generated in glycolysis) into the mitochondria.
Malate shuttle is not a part of the glycolytic process itself
Malate shuttle is a part of the gluconeogenic process.
Glycogenolysis
Glycolysis
Gluconeogenesis
HMP shunt