Glucose-6-Phosphate Dehydrogenase Deficiency in Nigerian Children

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common human enzymopathy and in Sub-Saharan Africa, is a significant cause of infection- and drug-induced hemolysis and neonatal jaundice. Our goals were to determine the prevalence of G6PD deficiency among Nigerian children of different ethnic backgrounds and to identify predictors of G6PD deficiency by analyzing vital signs and hematocrit and by asking screening questions about symptoms of hemolysis. We studied 1,122 children (561 males and 561 females) aged 1 month to 15 years. The mean age was 7.4±3.2 years. Children of Yoruba ethnicity made up the largest group (77.5%) followed by those Igbo descent (10.6%) and those of Igede (10.2%) and Tiv (1.8%) ethnicity. G6PD status was determined using the fluorescent spot method. We found that the overall prevalence of G6PD deficiency was 15.3% (24.1% in males, 6.6% in females). Yoruba children had a higher prevalence (16.9%) than Igede (10.5%), Igbo (10.1%) and Tiv (5.0%) children. The odds of G6PD deficiency were 0.38 times as high in Igbo children compared to Yoruba children (p = 0.0500). The odds for Igede and Tiv children were not significantly different from Yoruba children (p = 0.7528 and 0.9789 respectively). Mean oxygen saturation, heart rate and hematocrit were not significantly different in G6PD deficient and G6PD sufficient children. The odds of being G6PD deficient were 2.1 times higher in children with scleral icterus than those without (p = 0.0351). In conclusion, we determined the prevalence of G6PD deficiency in Nigerian sub-populations. The odds of G6PD deficiency were decreased in Igbo children compared to Yoruba children. There was no association between vital parameters or hematocrit and G6PD deficiency. We found that a history of scleral icterus may increase the odds of G6PD deficiency, but we did not exclude other common causes of icterus such as sickle cell disease or malarial infection.     

Glucose-6-Phosphate Dehydrogenase Deficiency and Physical and Mental Health until Adolescence

BackgroundTo examine the association of glucose-6-phosphate dehydrogenase (G6PD) deficiency with adolescent physical and mental health, as effects of G6PD deficiency on health are rarely reported.MethodsIn a population-representative Chinese birth cohort: “Children of 1997” (n = 8,327), we estimated the adjusted associations of G6PD deficiency with growth using generalized estimating equations, with pubertal onset using interval censored regression, with hospitalization using Cox proportional hazards regression and with size, blood pressure, pubertal maturation and mental health using linear regression with multiple imputation and inverse probability weighting.ResultsAmong 5,520 screened adolescents (66% follow-up), 4.8% boys and 0.5% girls had G6PD deficiency. G6PD-deficiency was not associated with birth weight-for-gestational age or length/height gain into adolescence, but was associated with lower childhood body mass index (BMI) gain (-0.38 z-score, 95% confidence interval (CI) -0.57, -0.20), adjusted for sex and parental education, and later onset of pubic hair development (time ratio = 1.029, 95% CI 1.007, 1.050). G6PD deficiency was not associated with blood pressure, height, BMI or mental health in adolescence, nor with serious infectious morbidity until adolescence.ConclusionsG6PD deficient adolescents had broadly similar physical and mental health indicators, but transiently lower BMI gain and later pubic hair development, whose long-term implications warrant investigation.     

Biochemical Characterization of Buffalo Liver Glucose-6-Phosphate Dehydrogenase Isoforms

Glucose-6-phosphate dehydrogenase (G6PD) is a key regulatory enzyme involved in the pentose phosphate pathway. This works represents purification of two buffalo liver glucose-6-phosphate dehydrogenases (BLG6PD1 and BLG6PD2) using combination of ammonium sulfate precipitation and several chromatographic columns. Both enzymes (BLG6PD1 and BLG6PD2) were homogenous on both native PAGE as well as 12 % SDS PAGE with molecular weights of 28 and 66 kDa. The molecular weight of BLG6PD1 and BLG6PD2 native forms were determined to be 28 and 66 kDa by gel filtration; indicating monomeric proteins. The K _m values for BLG6PD1 and BLG6PD2 estimated to be 0.059 and 0.06 mM of β-nicotinamide adenine dinucleotide phosphate. The optimum activity of BLG6PD1 and BLG6PD2 were displayed at pH 8.0 and 8.2 with an isoelectric point (pI) of pH 7.7–7.9 and 5.7–5.9. The divalent cations MgCl₂, and CoCl₂ act as activators, on the other hand, FeCl₂, CuCl₂ and ZnCl₂ are potent inhibitors of BLG6PD1 and BLG6PD2 activity. NADPH inhibited both isoenzymes competitively with Ki values of 0.012 and 0.030 mM. This study describes a reproducible purification scheme of G6PD from the liver of buffalo as a rich source.     

Characterization of Enterobacteria by Starch-Gel Electrophoresis of Glucose-6-Phosphate Dehydrogenase and Phosphogluconate Dehydrogenase

Specific activities and electrophoretic mobilities of glucose-6-phosphate dehydrogenase and phosphogluconate dehydrogenase were determined in 38 isolates of the family Enterobacteriaceae and in 10 isolates of the related Pasteurella. The deficiency of glucose-6-phosphate dehydrogenase in P. pestis was verified. Enzymes obtained from different strains of the same species exhibited an unexpected degree of heterogeneity. For example, 8 and 11 apparent variants of glucose-6-phosphate dehydrogenase and phosphogluconate dehydrogenase, respectively, were found in 14 strains of Escherichia coli. Although similar frequencies of heterogeneity were noted in 7 strains of P. pseudotuberculosis, 5 species of Shigella, and 8 species of Salmonella, differences in mobility were generally small in comparison with those observed between strains of E. coli. Values obtained for the pasteurellae, shigellae, and salmonellae, thus fell within narrow ranges that may prove typical for the genera. However, most of these ranges, as well as many values observed for single species of other genera, were overlapped by the wide range recorded for E. coli. The significance of this observation was discussed with respect to the relative age and taxonomic position of the organisms in question. The method could be used to distinguish between most wild-type strains of the same species and should thus facilitate investigations of genetic transfer and epidemiology.     

Purification and Characterization of Glucose-6-Phosphate Dehydrogenase from Rat Small Intestine

Glucose-6-phosphate dehydrogenase (G6PD) was purified from rat small intestine with 19.2% yield and had a specific activity of 53.8 units per miligram protein. The pH optimum was determined to be 8.1. The purified rat small intestinal G6PD gave one activity, one protein band on native PAGE. The observation of one band on SDS/PAGE with an Mr of 48 kDa and a specific activity lower than expected may suggest the proteolytically affected enzyme or different form of G6PD in the rat small intestine. The activation energy, activation enthalpy, Q10, and optimum temperature from Arrhenius plot for the rat small intestinal G6PD were found to be 8.52 kcal/mol, 7.90 kcal/mol, 1.59, and 38 degrees C, respectively. The Km values for G6P and NADP+ were 70.1 +/- 20.8 and 23.2 +/- 7.6 microM, respectively. Double-reciprocal plots of 1/Vm versus 1/G6P (at constant [NADP+]) and of 1/Vm versus 1/NADP+ at constant [G6P]) intersected at the same point on the 1/Vm axis to give Vm = 53.8 U/mg protein.     

Glucose-6-Phosphate Dehydrogenase/6-Phosphogluconate Dehydrogenase Ratio and the Glucose-6-Phosphate, 6-Phosphogluconate and Fructose-6-Phosphate Contents in Tobacco Plants Infected with Potato Virus Y

The ratio of activities of glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase (G6P DH/6PG DH), and the contents of glucose-6-phosphate (G6P), 6-phosphogluconate (6PG) and fructose-6-phosphate (F6P) were studied at various stages of potato virus Y (PVY) multiplication in Nicotiana tabacum cv. Samsun. G6P DH/6PG DH increased through the experiment from 0.42 to 0.53 in leaves of healthy tobacco, and up to 0.59 in PVY systemically infected leaves. However, these ratios in the ruptured protoplast preparations, and the chloroplast and cytosol fractions of healthy protoplasts were similar to that from infected ones. The ratio lower than 1, found in the healthy and/or PVY- infected leaf tissues and in the infected protoplasts as well, confirms the assumption that G6P DH is the control enzyme of oxidative pentosephosphate pathway not only in the healthy but also in the infected plants. The contents of G6P, 6PG and F6P in the period of the highest PVY multiplication were strongly decreased (to 30 – 50 % when compared with control healthy leaves) and were negatively correlated with the G6P DH and 6PG DH activities.     

Glucose-6-Phosphate Dehydrogenase from the Chemolithotroph Thiobacillus ferrooxidans

Glucose-6-phosphate dehydrogenase was partially purified from both glucose-grown and iron-glucose-grown Thiobacillus ferrooxidans. The enzyme possesses a dual nucleotide specificity for either nicotinamide adenine dinucleotide phosphate (NADP) or nicotinamide adenine dinucleotide (NAD) and has a molecular weight of 110,000 as determined by gel electrophoresis. Evidence is presented that T. ferrooxidans glucose-6-phosphate dehydrogenase is identical when isolated from cells grown mixotrophically (iron-glucose grown) or cells grown heterotrophically (glucose-grown cells). The enzyme is activated by Mg(2+), and to a lesser extent by low concentrations of Mn(2+). Reduced NAD inhibits the enzyme from T. ferrooxidans. No deviation from normal Michaelis-Menten kinetics was observed in velocity versus substrate concentration experiments. Adenosine triphosphate exerted a profound inhibition of the enzyme; the effect was 10 times more pronounced in the presence of NAD as compared to NADP. The physiological significance of this inhibition is discussed.     

Deactivation of Glucose-6-Phosphate Dehydrogenase by Light-Reduced Thioredoxin

The activity of glucose-6-phosphate dehydrogenase (G6PDH, E. C. 1.1.1.49) in a reconsituted pea chloroplast system was assayed spectrophotometrically by the reduction of NADP, ming glucose-6-phosphate as substrate. Deactivation of G6PDH could be intensified by adding lightreduced thioredoxin (Td) into the reconstituted chloroplast system. The experimental results presented suggest that Td plays an important role not only in the dark activation, but also in the light deactivation of G6PDH in chloroplasts. There were two isozymes of G6PDH in green and in etiolated pea seedlings. The effects of dithiothreitol (DTT) and Td on G6PDH in etiolated seedlings were different from that in chloroplasts. The light regulation of G6PDH in chloroplasts is mediated through Td.     

Genetic Mapping of Loci for Glucose-6-Phosphate Dehydrogenase, Gluconate-6-Phosphate Dehydrogenase, and Gluconate-6-Phosphate Dehydrase in Escherichia coli

The loci on the Escherichia coli genome of mutations affecting the constitutive enzymes glucose-6-phosphate dehydrogenase (zwf) and gluconate-6-phosphate dehydrogenase (gnd), and the inducible enzyme gluconate-6-phosphate dehydrase (edd), were determined by conjugation and transduction experiments, chiefly by three-factor crosses. They are in the same region of the chromosome, and their order is gnd-his-(edd, zwf)-aroD; gnd and his are cotransduceable, as are zwf and edd. The position of gnd in Salmonella typhimurium was shown to be similar to that in E. coli.     

高等植物葡萄糖-6-磷酸脱氢酶与6-磷酸葡萄糖酸脱氢酶基因的不同进化起源

葡萄糖-6-磷酸脱氢酶与6-磷酸葡萄糖酸脱氢酶是植物戊糖磷酸途径中的两个酶.在克隆了水稻质体葡萄糖-6-磷酸脱氢酶基因OsG6PDH2和质体6-磷酸葡萄糖脱氢酶基因Os6PGDH2基础上,分析比较了水稻胞质和质体葡萄糖-6-磷酸脱氢酶基因和6-磷酸葡萄糖酸脱氢酶基因的基因结构、表达特性和进化地位.结合双子叶模式植物拟南芥两种酶基因的分析结果,认为高等植物葡萄糖-6-磷酸脱氢酶基因和6-磷酸葡萄糖酸脱氢酶基因在进化方式上截然不同,葡萄糖-6-磷酸脱氢酶的胞质基因与动物和真菌等真核生物具有共同的祖先;6-磷酸葡萄糖酸脱氢酶的胞质酶和质体酶基因都起源于原核生物的内共生.讨论了植物葡萄糖-6-磷酸脱氢酶与6-磷酸葡萄糖酸脱氢酶基因可能的进化模式,为高等植物及质体的进化起源提供了新的资料.     

高等植物葡萄糖-6- 磷酸脱氢酶与6- 磷酸葡萄糖酸脱氢酶基因的不同进化起源

葡萄糖-6-磷酸脱氢酶与6-磷酸葡萄糖酸脱氢酶是植物戊糖磷酸途径中的两个关键酶。在克隆了水稻质体葡萄糖-6-磷酸脱氢酶基因OsG6PDH2和质体6-磷酸葡萄糖脱氢酶基因Os6PGDH2基础上,分析比较了水稻胞质和质体葡萄糖-6-磷酸脱氢酶基因和6-磷酸葡萄糖酸脱氢酶基因的基因结构、表达特性和进化地位。结合双子叶模式植物拟南芥两种酶基因的分析结果,认为高等植物葡萄糖-6-磷酸脱氢酶基因和6-磷酸葡萄糖酸脱氢酶基因在进化方式上截然不同,葡萄糖-6-磷酸脱氢酶的胞质基因与动物和真菌等真核生物具有共同的祖先;6-磷酸葡萄糖酸脱氢酶的胞质酶和质体酶基因都起源于原核生物的内共生。讨论了植物葡萄糖-6-磷酸脱氢酶与6-磷酸葡萄糖酸脱氢酶基因可能的进化模式,为高等植物及质体的进化起源提供了新的资料。     

Prevalence of Glucose-6-Phosphate Dehydrogenase (G6PD) Deficiency among Malaria Patients in Southern Thailand: 8 Years Retrospective Study

Erythrocytes deficient in glucose-6-phosphate dehydrogenase (G6PD) is more susceptible to oxidative damage from free radical derived compounds. The hemolysis triggered by oxidative agents such as primaquine (PQ) is used for the radical treatment of hypnozoites of P. vivax. Testing of G6PD screening before malaria treatment is not a common practice in Thailand, which poses patients at risk of hemolysis. This retrospective study aimed to investigate the prevalence of G6PD in malaria patients who live in Southern Thailand. Eight hundred eighty-one malaria patients were collected for 8-year from 2012 to 2019, including 785 (89.1%) of P. vivax, 61 (6.9%) of P. falciparum, 27 (3.1%) of P. knowlesi, and 8 (0.9%) of mixed infections. The DiaPlexC genotyping kit (Asian type) and PCR-RFLP were employed to determine the G6PD variants. The result showed that 5 different types of G6PD variants were identified in 26 cases (2.9%); 12/26 (46.2%) had Mahidol (487G>A) and 11/26 (42.3%) had Viangchan (871G>A) variants, while the rest had Kaiping (1388G>A), Union (1360C>T), and Mediterranean (563C>T) variants. G6PD Songklanagarind (196T>A) variant was not found in the study. Our result did not show a significant difference in the malaria parasite densities in patients between G6PD-deficient and G6PD-normal groups. According to our findings, testing G6PD deficiency and monitoring the potential PQ toxicity in patients who receive PQ are highly recommended.     

Purification and Characterization of the Pseudomonas multivorans Glucose-6-Phosphate Dehydrogenase Active with Nicotinamide Adenine Dinucleotide

The Pseudomonas multivorans glucose-6-phosphate dehydrogenase (EC 1.1.1.49) active with nicotinamide adenine dinucleotide, which is inhibitable by adenosine-5'-triphosphate, was purified approximately 1,000-fold from extracts of glucose-grown bacteria, and characterized with respect to subunit composition, response to different inhibitory ligands, and certain other properties. The enzyme was found to be an oligomer composed of four subunits of about 60,000 molecular weight. Reduced nicotinamide adenine dinucleotide phosphate, but not reduced nicotinamide adenine dinucleotide, was found to be a potent inhibitor of its activity. The range of concentrations of reduced nicotinamide adenine dinucleotide phosphate over which inhibition occurred was about 100-fold lower than that for adenosine-5'-triphosphate. The data suggest that reduced nicotinamide adenine dinucleotide phosphate may play an important role in regulation of hexose phosphate metabolism in P. multivorans. Antisera prepared against the purified enzyme strongly inhibited its activity, but failed to inhibit the activity of the nicotinamide adenine dinucleotide phosphate-specific glucose-6-phosphate dehydrogenase which is also present in extracts of this bacterium. Immunodiffusion experiments confirmed the results of the enzyme inhibition studies, and failed to support the idea that the two glucose-6-phosphate dehydrogenase species from P. multivorans represent different oligomeric forms of the same protein.