The active NAD-dependent glutamate dehydrogenase of wild type yeast cells fractionated by DEAE-Sephacel chromatography was inactivated in vitro by the addition of either the cAMP-dependent or cAMP-independent protein kinases obtained from wild type cells. cAMP-dependent inhibition of glutamate dehydrogenase activity was not observed in the crude extract of bcy1 mutant cells which were deficient...

During the last several years, evidence that various enzymes hydrolyze NAD into bioactive products prompted scientists to revisit or design strategies able to increase intracellular availability of the dinucleotide. However, plasma membrane permeability to NAD and the mitochondrial origin of the dinucleotide still wait to be clearly defined. Here, we report that intracellular NAD contents incre...

ELD, ELT/B1, Krebs II, and Sarcoma 180 ascites tumor cells were examined for the mitochondria! malic enzymes. The nicotinamide adenine dinucleotide (phosphate) [NAD(P) ]-dependent malic enzyme was present in all mitochondria! fractions at activities that ranged from 21 to 27 nmol reduced nicotinamide adenine dinucleotide formed per min per mg mitochondria! protein. As judged by kinetic properti...

NAD(+) and NADH play crucial roles in a variety of biological processes including energy metabolism, mitochondrial functions, and gene expression. Multiple studies have indicated that NAD(+) administration can profoundly decrease oxidative cell death as well as ischemic and traumatic brain injury, suggesting NAD(+) metabolism as a promising therapeutic target for cerebral ischemia and head inju...

Aldehyde dehydrogenase 1A1 (ALDH1A1) is a member of the aldehyde dehydrogenase superfamily that oxidizes aldehydes to their corresponding acids, reactions that are coupled to the reduction of NAD+ to NADH. We report here that ALDH1A1 can also use glutathione (GSH) and dihydrolipoic acid (DHLA) as electron donors to reduce NAD+ to NADH. The GSH/DHLA-dependent NAD+-reduction activity of ALDH1A1 i...

Accumulating evidence has suggested that NAD (including NAD+ and NADH) and NADP (including NADP+ and NADPH) could belong to the fundamental common mediators of various biological processes, including energy metabolism, mitochondrial functions, calcium homeostasis, antioxidation/generation of oxidative stress, gene expression, immunological functions, aging, and cell death: First, it is establis...

Glutamate dehydrogenase (GDH) catalyses the reversible conversion of glutamate into α-ketoglutarate with the concomitant reduction of NAD(P)(+) to NAD(P)H or vice versa. GDH activity is subject to complex allosteric regulation including substrate inhibition. To determine GDH kinetics in situ, we assessed the effects of various glutamate concentrations in combination with either the coenzyme NAD...

Yeast deprived of nutrients exhibit a marked life span extension that requires the activity of the NAD(+)-dependent histone deacetylase, Sir2p. Here we show that increased dosage of NPT1, encoding a nicotinate phosphoribosyltransferase critical for the NAD(+) salvage pathway, increases Sir2-dependent silencing, stabilizes the rDNA locus, and extends yeast replicative life span by up to 60%. Bot...

NAD-independent lactate dehydrogenases are commonly thought to be responsible for lactate utilization during the stationary phase of aerobic growth in Lactobacillus plantarum. To substantiate this view, we constructed single and double knockout mutants for the corresponding genes, loxD and loxL. Lactate-to-acetate conversion was not impaired in these strains, while it was completely blocked in ...