From the Guidelines
NADPH Catabolism
NADPH is not inherently catabolic, as it serves as a reducing agent in various anabolic reactions, including fatty acid biosynthesis and to combat oxidative stress 1.
- The generation of NADPH is crucial for anabolic processes, and its catabolism is not a primary physiological process.
- NADPH is a crucial cofactor for enzymes involved in these processes, and its degradation is not typically targeted by therapeutic interventions.
- In cellular metabolism, NADPH plays a key role in maintaining redox homeostasis by oxidizing excess NADH generated in central metabolic pathways 1.
- The focus of therapeutic interventions, including medications, is often on influencing NADPH levels indirectly through effects on glucose and lipid metabolism, rather than targeting its catabolism directly.
- NADPH is essential for various cellular functions, and its anabolic role is more significant than its potential catabolic processes 1.
From the Research
NADPH Catabolic Role
- NADPH is involved in both anabolic and catabolic pathways, as stated in the study 2
- It participates in several biochemical reactions involving energy release, indicating its role in catabolic processes 2
- The study 3 found that the bifunctional malic/malolactic enzyme in Bacillus subtilis provides a novel mechanism for NADPH-balancing, which involves the conversion of NADPH to NADH, a catabolic process
- Another study 4 discovered that mitochondrial complex I inhibition triggers NAD+-independent glucose oxidation via successive NADPH formation, "futile" fatty acid cycling, and FADH2 oxidation, which also involves catabolic processes
NADPH Production and Utilization
- NADPH is supplied by the oxidative branch of the pentose phosphate pathway and by enzymes associated with the citric acid cycle, as mentioned in the study 5
- The study 6 highlights the importance of glucose-6-phosphate dehydrogenase in producing NADPH, which is essential for cell survival and various cellular processes
- The production and utilization of NADPH are crucial for maintaining the balance of redox cofactors in the cell, as discussed in the study 3
Enzymatic Reactions Involving NADPH
- The study 2 reports the use of glucose-6-phosphate dehydrogenase immobilized onto magnetic beads to produce high amounts of NADPH, which can be used in various enzymatic reactions
- The bifunctional malic/malolactic enzyme in Bacillus subtilis can switch its activity from a pyruvate-producing malic enzyme to a lactate-generating malolactic enzyme, depending on NADPH availability, as found in the study 3
- The study 4 found that complex I inhibition leads to a metabolic shift from glycolysis and the citric acid cycle to the pentose phosphate pathway, resulting in the production of NADPH, which is then converted to FADH2 through fatty acid cycling.