Nicotinamide adenine dinucleotide metabolism in plants. I. Intermediates of biosynthesis in wheat leaves and the effect of benzimidazole

1970 ◽  
Vol 48 (12) ◽  
pp. 2267-2278 ◽  
Author(s):  
H. R. Godavari ◽  
E. R. Waygood

Leaves of wheat (Triticum aestivum L. var. Selkirk) were incubated with nicotinic acid-7-14C and nicotinamide-7-14C for varying time periods from 5 min to 12 h. Aliquots of alcoholic extracts of leaves were subjected to paper chromatography and radioautography to isolate the intermediates of the synthesis and breakdown of nicotinamide adenine dinucleotide. Nine compounds were isolated quantitatively and identified as intermediates in the pathway of NAD metabolism. All the intermediates were labeled rapidly and the rapidity of labeling became a problem in rigorously proving the sequential operation of the pathway. The results indicate that the Preiss-Handler pathway: nicotinic acid→nicotinic acid mononucleotide→nicotinic acid adenine dinucleotide→NAD operates in wheat leaves. The degradation of NAD proceeded from NAD→nicotinamide mononucleotide→nicotinamide riboside→nicotinamide. Deamidation of the nicotinamide to nicotinic acid initiated a fresh cycle of biosynthesis. The total radioactivity recovered in the intermediates indicates that no measurable amount was lost to other metabolic pathways. Nicotinamide is recovered without significant loss and recycled. The rapid appearance of labeled nicotinamide indicates a possible interconversion of nicotinic acid and nicotinamide. About 80% of the radioactivity accumulated was present in trigonelline which is considered, on the basis of other evidence, to be a non-toxic form of nicotinic acid. Benzimidazole treatment of the leaves increased the incorporation of 14C into NADP.

2020 ◽  
Vol 5 (3) ◽  
pp. 182-198
Author(s):  
Fatemeh Ghorbania ◽  
◽  
Masoomeh Ghorbani ◽  
Arezou Ghahghaee ◽  

Diabetes is a group of metabolic disorders characterized by a high blood sugar level over a prolonged period of time. Inhibition of carbohydrate hydrolyzing enzymes leads to decrease in the absorption of glucose which is considered as one of the effective managements of diabetes mellitus. Vegetable, fruit, milk and fish are good sources of nucleosides and inosine (INO), nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN) with versatile health benefits. The well-adapted structural features of these compounds for the inhibition/activation of enzymes include several available hydrogen bond (H-bond) acceptors and donors, flexible backbone and hydrophobic nature. The substrates of α-amylase (α-Amy) and α-Glucosidase (α-Glu), known as key absorbing enzymes, have functional groups (OH groups) resembling nucleosides. Therefore, the present study was conducted to evaluate the inhibitory properties of nucleosides against αAmy and α-Glu. The median inhibition concentration (IC50) values for α-Glu in the presence of adenosine (ADN), adenosine triphosphate (AMP), NR, INO, adenosine triphosphate (ATP), nicotinamide adenine dinucleotide (NAD), Adenosine diphosphate (ADP)-ribose, ADP-glucose and NMN were determined 208.6±3.8, 254.1±5.2, 177.7±4.8, 192.1±5.2, 215.9±2.7, 65.4±1.3, 63.4±2.2, 75.6±4.2 and 196.1±2.6, respectively. The IC50 values α-Amy in the presence of ADN, AMP, NR, INO, ATP, NAD, ADP-ribose, ADP-glucose and NMN were determined 145.3±2.4, 202.3±3.9, 127.7±4.8, 163.5±3.6, 185.3±1.2, 80.4±2.8, 64.8±4.7, 51.1±1.6 and 166.5±1.4, respectively. Moreover, the Ki values of NAD were calculated as 13.8±0.8 and 18.6±2.4 µM for α-Glu and α-Amy in a competitive-mode and noncompetitive -mode inhibition. In addition, to communicate with the active site of α-Glu and α-Amy respectively, NR presented a binding energy of -7.8 and -6.8 kcal/mol, INO -7.3 and -6.9, ATP -8.3 and -7.3, NAD -10.0 and -8.5, ADP-ribose -8.7 and -7.4, ADP-glucose -8.9 and -7.6, cAMP -6.6 and -6.3 and NMN -6.8 and -7.0 kcal/mol. These antioxidant inhibitors may be potential anti-diabetic drugs, not only to reduce glycemic index, but also to limit the activity of the major reactive oxygen species (ROS) producing pathways. Key words: Nucleosides, NAD, hydrolyzing enzymes, enzyme inhibition, hyperglycemia


1974 ◽  
Vol 52 (4) ◽  
pp. 707-713 ◽  
Author(s):  
S. C. Chen ◽  
H. R. Godavari ◽  
E. R. Waygood

Incorporation of nicotinic acid-7-14C into nicotinamide adenine dinucleotide by the trifoliate leaves of the bean plant (Phaseolus vulgaris L. var. Brittle Wax) was studied for varying time periods from 5 min to 48 h. Nine radioactive compounds were isolated and identified as all the possible intermediates of NAD metabolism operating in a cyclic pattern. All the intermediates were labelled rapidly and N-methyl nicotinic acid (trigonelline) was detected within 5 min. About 80% of the nicotinic acid fed was accumulated in trigonelline. Senescence induced by floating detached leaves on water enhanced incorporation of the label into nucleotides, NAD > NADP. Treatment with growth regulators altered the NAD/NADP ratios. Benzimidazole and kinetin enhanced NADP synthesis while benzyladenine and ethionine reduced NADP synthesis. The regulator-mediated NADP synthesis is enhanced by light and appears to be inversely related to the synthesis of trigonelline.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Ayushi Chaurasiya ◽  
Swati Garg ◽  
Ashish Khanna ◽  
Chintam Narayana ◽  
Ved Prakash Dwivedi ◽  
...  

AbstractHijacking of host metabolic status by a pathogen for its regulated dissemination from the host is prerequisite for the propagation of infection. M. tuberculosis secretes an NAD+-glycohydrolase, TNT, to induce host necroptosis by hydrolyzing Nicotinamide adenine dinucleotide (NAD+). Herein, we expressed TNT in macrophages and erythrocytes; the host cells for M. tuberculosis and the malaria parasite respectively, and found that it reduced the NAD+ levels and thereby induced necroptosis and eryptosis resulting in premature dissemination of pathogen. Targeting TNT in M. tuberculosis or induced eryptosis in malaria parasite interferes with pathogen dissemination and reduction in the propagation of infection. Building upon our discovery that inhibition of pathogen-mediated host NAD+ modulation is a way forward for regulation of infection, we synthesized and screened some novel compounds that showed inhibition of NAD+-glycohydrolase activity and pathogen infection in the nanomolar range. Overall this study highlights the fundamental importance of pathogen-mediated modulation of host NAD+ homeostasis for its infection propagation and novel inhibitors as leads for host-targeted therapeutics.


2021 ◽  
Author(s):  
Masaki Igarashi ◽  
Masaomi Miura ◽  
Yoshiko Nakagawa-Nagahama ◽  
Keisuke Yaku ◽  
Kosuke Kashiwabara ◽  
...  

Abstract Preclinical studies have revealed that the elevation of nicotinamide adenine dinucleotide (NAD+) levels on administration of an NAD+ precursor, nicotinamide mononucleotide (NMN), can mitigate aging-related disorders; however, human data are sparse. Therefore, we aimed to investigate whether the chronic oral supplementation of NMN can elevate blood NAD+ levels and alter physiological dysfunctions, including muscle weakness, in healthy elderly participants. We administered 250 mg NMN per day to aged men for 6 or 12 weeks (n=21 for 6 weeks, n=10 for 12 weeks) in a placebo-controlled, randomized, double blind, parallel-group trial. Chronic supplementation with NMN was well tolerated and did not cause any significant deleterious effect. Metabolomic analysis of whole blood demonstrated that the oral supplementation of NMN significantly increased the concentrations of NAD+ and NAD+ metabolites. Moreover, NMN significantly improved muscle strength and performance, which were evaluated using the 30-second chair stand test, walking speed, and grip strength, and it showed no significant effect on body composition. Thus, our evidence indicates that chronic oral NMN supplementation can be an efficient NAD+ booster for preventing aging-related muscle dysfunctions in humans.


Blood ◽  
1990 ◽  
Vol 75 (8) ◽  
pp. 1705-1710 ◽  
Author(s):  
CR Zerez ◽  
EF Jr Roth ◽  
S Schulman ◽  
KR Tanaka

Abstract Plasmodium falciparum-infected red blood cells (RBCs) are characterized by increases in the activity of glycolytic enzymes. Because nicotinamide adenine dinucleotide (NAD) and NAD phosphate (NADP) are cofactors in the reactions of glycolysis and pentose phosphate shunt, we have examined NAD and NADP content in P. falciparum-infected RBCs. Although NADP content was not significantly altered, NAD content was increased approximately 10-fold in infected RBCs (66% parasitemia) compared with uninfected control RBCs. To determine the mechanism for the increase in NAD content, we examined the activity of several NAD biosynthetic enzymes. It is known that normal human RBCs make NAD exclusively from nicotinic acid and lack the capacity to make NAD from nicotinamide. We demonstrate that infected RBCs have readily detectable nicotinamide phosphoribosyltransferase (NPRT), the first enzyme in the NAD biosynthetic pathway that uses nicotinamide, and abundant nicotinamide deamidase, the enzyme that converts nicotinamide to nicotinic acid, thereby indicating that infected RBCs can make NAD from nicotinamide. In addition, infected RBCs have a threefold increase in nicotinic acid phosphoribosyltransferase (NAPRT), the first enzyme in the NAD biosynthetic pathway that uses nicotinic acid. Thus, the increase in NAD content in P falciparum-infected RBCs appears to be mediated by increases in NAD synthesis from both nicotinic acid and nicotinamide.


2020 ◽  
Vol 21 (13) ◽  
pp. 4655
Author(s):  
Duo Feng ◽  
DongZhu Xu ◽  
Nobuyuki Murakoshi ◽  
Kazuko Tajiri ◽  
Rujie Qin ◽  
...  

Aging and obesity are the most prominent risk factors for onset of atrial fibrillation (AF). Nicotinamide phosphoribosyltransferase (Nampt) is the rate-limiting enzyme that catalyzes nicotinamide adenine dinucleotide (NAD) activity. Nampt and NAD are essential for maintenance of cellular redox homeostasis and modulation of cellular metabolism, and their expression levels decrease with aging and obesity. However, a role for Nampt in AF is unknown. The present study aims to test whether there is a role of Nampt/NAD axis in the pathogenesis of obesity-induced AF. Male C57BL/6J (WT) mice and heterozygous Nampt knockout (NKO) mice were fed with a normal chow diet (ND) or a high-fat diet (HFD). Electrophysiological study showed that AF inducibility was significantly increased in WT+HFD, NKO+ND, and NKO+HFD mice compared with WT+ND mice. AF duration was significantly longer in WT+HFD and NKO+ND mice and further prolonged in NKO+HFD mice compared with WT+ND mice and the calcium handling pathway was altered on molecular level. Also, treatment with nicotinamide riboside, a NAD precursor, partially restored the HFD-induced AF perpetuation. Overall, this work demonstrates that partially deletion of Nampt facilitated HFD-induced AF through increased diastolic calcium leaks. The Nampt/NAD axis may be a potent therapeutic target for AF.


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