NNT (Nicotinamide Nucleotide Transhydrogenase): Nicotinamide Nucleotide Transhydrogenase (NNT) is an enzyme located in the inner mitochondrial membrane that plays a key role in regenerating NADPH from NADH. This process is essential for maintaining the cellular redox balance and protecting cells from oxidative stress. Deficiencies in NNT can impair mitochondrial function and increase vulnerability to oxidative damage, contributing to metabolic disorders and chronic diseases.