Purification and characterization of 6-phosphogluconate dehydrogenase (6-PGD) from grass carp (Ctenopharyngodon idella) hepatopancreas.

6-Phosphogluconate dehydrogenase (6-PGD, E.C.: 1.1.1.44) was purified and characterized from the hepatopancreas of grass carp (Ctenopharyngodon idella) for the first time. Grass carp represents the second largest aquaculture industry in the world after silver carp, constituting 14.7% of the world aquaculture production, with an average annual increase of 14% in China, mainly as a source of food. The purification procedure involved a single 2’, 5’-ADP-Sepharose 4B affinity chromatographic step by using different elution buffers. The enzyme was purified 309-fold with a specific activity of 5.259 U/mg protein and yield of 68%. The purity and subunit molecular weights of the 6-PGD were checked on SDS-PAGE and purified enzyme showed a single band on the gel. The subunit molecular mass was 57 kDa, with an optimum pH, temperature and ionic strength at 7.96, 50oC and 100 mM Tris-HCl, respectively. The Km values of 6-PGA and NADP+ were 0.019 and 0.0052 mM, respectively, while Vm of 6-PGA and NADP+ was 0.69 U/ml. Dissociation constants (Ki) for 6-PGA and NADP+ were 2.05 and 0.12 mM, respectively. NADPH inhibited the enzyme in a competitive manner and its Ki value was 0.032 mM. The Cu2+, Zn2+, Cd2+ and Al3+ showed inhibitory effects on the enzyme with IC50 values of 0.293, 0.099, 0.045 and 1.526 mM, respectively. All tested metals inhibited the enzyme in a competitive manner, indicating that these metals might be toxic even at low concentrations for the 6-PGD. As the fish is one of valuable foodstuff of animal sources for human consumption, under certain environmental conditions, metal ions accumulated in fish up to a lethal concentration may be harmful for human health. Therefore, it is impending to reduce the concentration of metal ions in contaminated lakes and rivers for fishery and also for human health.

Hypoglycemic effect of Rehmannie Radix Preparata (Sookjihwang) extract in streptozotocin-induced diabetic rats

Rhemannie Radix Preparata (RRP) has been previously employed in traditional oriental medicine as a treatment for diabetic thirst and improving blood flow. The aim of this study was to evaluate its hypoglycemic control by assaying the activities of key enzymes of carbohydrate metabolism in streptozotocin-(STZ)-induced diabetic rats. Further, RRP extracts were prepared in water (RRPW), in 50% ethanol (RRP50), and in 100% ethanol (RRP100), respectively, and compared for their actions in diabetic rats. The oral treatment of RRP (5 mg/kg b.w./d) to diabetic rats for 21 days resulted in a significant decline in blood glucose by 67% compared to diabetic control rats (P < 0.05). The altered activities of glucokinase, glucose-6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6PGD), and acetyl CoA carboxylase (ACC) in the livers of diabetic rats were reversed significantly to near-normal levels by the administration of RRP (P < 0.05). Among the three RRP extracts, RRP100 was the most effective in terms of hypoglycemic action. However, the administration of RRP to diabetic rats did not improve insulin production. The modulatory effects of RRP100 on the attenuation of carbohydrate enzyme activities appear to hold promise for widespread use for the treatment of diabetes in the future.

Role of bilirubin as antioxidant in neonatal jaundice and effect of ethanolic extract of sweet lime peel on experimentally induced jaundice in rat.

Bilirubin above a threshold level is toxic to human system and is excreted in urinary and through gastrointestinal tract. The role of bilirubin as antioxidant is debatable. This paper aims at elucidating the role of bilirubin as an antioxidant in neonatal jaundice patients. It is observed that bilirubin up to 6 mg/dl in blood acts as an antioxidant and above 12.5 mg/dl is strongly prooxidant. Phototherapy is the accepted therapeutic management of neonatal jaundice and has been shown to enhance the oxidative stress. Approaches have been taken to formulate a herbal medication which will reduce bilirubin level in the neonates without inducing additional damages. The ethanolic extract of sweet lime peel, administered orally at a dose of 72 microg is found to reduce the oxidative stress in erythrocytes of phenylhydrazine-induced jaundiced rats treated with phototherapy.

Evaluation of isoenzyme patterns for identification of pathogenic poultry Mycoplasmas

Electrophoretic analysis of isoenzymes in 8 enzymatic systems were used for differentiation of 4 isolates of chicken Mycoplasmas including two strains of M gallisepticum, one strain of M. gallinarum and one unknown isolate in comparison with a vaccinal strain of M agalactiae that basically is a pathogen in small ruminants. The enzymatic systems were lactate dehydrogenase [LDH], glucose dehydrogenase [G1DH], glucose 6 phosphate dehydrogenase [G6PD], galactose dehydrogenase [GalDH], 6 phosphogluconate dehydrogenase [6PGDH], malic enzyme [ME], glucose phosphate isomerase [GPI] and alkaline phosphatase [AP]. The number of isoenzyme patterns obtained for LDH, G1DH, G6PD, GalDH, 6PGDH, ME, GPI and AP enzymatic systems were 2, 3, 2, 4, 2, 3, 3 and 0, respectively. Except AP enzyme system which is not active in Mycoplasma species, it is concluded that isoenzyme pattern of 7 other studied enzymatic systems, could differentiate between chicken Mycoplasmas and the small ruminant's strain. Based on the isoenzyme patterns of GalDH system, 2 strains of M gallisepticum were differentiated from M. gallinarum and the unknown isolate. Isoenzyme patterns of ME system was able to differentiate M gallinarum from the other chicken isolates. The isoenzyme patterns of GPI system were different for the two strains of M gallisepticum. The isoenzyme patterns of GalDH, GPI and ME systems, showed that the unknown strain of chicken Mycoplasma is a strain of M gallisepticum and it is closely related to one of the known M. gallisepticum isolates

Short-term effects of thyroid hormones on lipogenic enzymes and 14C-acetate incorporation into various lipid classes: in vivo and in vitro studies.

Short-term effect of 3,5,3'-triiodothyronine (T3) and 3,5-diiodothyronine (T2) on lipid metabolism in the liver of Anabas testudineus was examined. In vivo injections of both T3 and T2 at a concentration of 10 ng/g body weight increased malic enzyme (ME), glucose-6-phosphate dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6PGDH) activity compared to 6-propylthiouracil (6-PTU) treated group. Treatment of 6-PTU results in the accumulation 14C-acetate into fat and thyroid hormones' treatment reduce it. In vitro experiments show that malic enzyme activity is augmented only by high concentration of T3 (10(-7) M) where as all concentrations of T2 increase its activity. In vitro studies with T3 showed a biphasic effect on cholesterol content. Conversely T2 in vitro, reduced cholesterol content with all concentrations. From these results it can be concluded that both T3 and T2 have short-term effect on lipid metabolism in Anabas.

Sequence polymorphism from EST data in sugarcane: a fine analysis of 6-phosphogluconate dehydrogenase genes

O presente estudo apresenta resultados preliminares demonstrando a utilizaçäo da base de dados de ESTs de cana-de-açúcar para detectar polimorfismo de base única (SNP para Single Nucleotide Polymorphism). Sessenta e quatro ESTs relacionados aos genes da 6-phosphogluconate deshydrogenases (Pgds) foram identificados e divididos em dois conjuntos bem delimitados, de 14 e 50 ESTs, correspondendo a dois genes, A e B. O alinhamento das seqüências do grupo A permitiu a detecçäo de um único SNP e o alinhamento das seqüências do grupo B permitiu a detecçäo de 39 SNP, incluindo 27 na regiäo codificante do gene. Trinta e oito SNP foram bi-nucleotídicos e um único tri-nucleotídico. Nove inserções/supressões de um até 72 pares de base foram detectados nas regiões näo- codificantes 3' ou 5'. A robustez e as conseqüências dessas observações preliminares säo discutidas.

Effect of alloxan induced mild insulin dependent diabetes mellitus on rat erythrocyte cytosolic dehydrogenases.

In order to understand how the red cell of mild insulin dependent diabetes mellitus rat perform the normal physiological function and maintain integrity cytosolic dehydrogenases were assayed. Lactate dehydrogenase produces the cofactor for glycolytic enzymes while glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase produces the coenzymes for oxygen radical scavanging enzymes. Decrease in activity of cytosolic dehydrogenase renders diabetic erythrocyte population more susceptible to oxidant stress.

Inhibition of two HMP shunt pathway enzymes by fatty acids and their CoA esters in developing human brain: role of fatty acid binding protein.

Inhibitory effects of fatty acids and their CoA esters on glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase activities of human fetal brain cytosol have been studied. Purified human fetal brain fatty acid binding protein reverses the inhibitory effects of palmitoyl-CoA and oleic acid on glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase activities in human fetal brain cytosol. This protein, when added alone, activates the enzymes. Levels of fatty acid binding proteins as well as the activities of these two HMP shunt pathway enzymes, which provide cofactors like NADPH for reductive biosynthesis, increase with gestation. These results indicate that a relationship exists between the high demand for fatty acids and synthesis of cofactors for lipid biosynthesis in developing brain.

Effects of prolactin and androgens on enzymes of carbohydrate metabolism in prostate of castrated bonnet monkeys Macaca radiata (Geoffroy).

Effects of prolactin (PRL), bromocriptine (Br), testosterone propionate (TP), dihydrotestosterone (DHT) and the combinations of these androgens with PRL/Br on the specific activities of caudal and cranial prostatic cellular enzymes involved in carbohydrate metabolism in castrated mature bonnet monkeys have been studied. Castration decreased all the enzymes studied such as hexokinase (HK), 6-phosphofructokinase (6-PFK), glyceraldehyde-3-phosphate dehydrogenase (G-3-PD), pyruvate kinase (PK), glucose-6-phosphate dehydrogenase (G-6-PD) and 6-phosphogluconate dehydrogenase (6-PGD) in the cranial and caudal prostates. PRL elevated the activities of all the enzymes above normal except G-3-PD of cranial lobe. In the caudal lobe, PRL brought back the activities of HK, PFK, PK, G-6-PD to normal and 6-PGD above normal except G-3-PD. TP/DHT treatment increased all the enzymes in both the lobes. PRL given along with TP/DHT further enhanced the androgen action with regard to HK, PK, G-6-PD and 6-PGD of cranial and PFK, G-3-PD, PK, G-6-PD and 6-PGD of caudal lobe. Br treatment did not produce any alteration of these enzymes in both the lobes. In the cranial lobe, during Br+TP/DHT treatment, the stimulating effects of androgen were unaffected on all the enzymes except PK. On the other hand in the caudal, the stimulatory effects of androgens were affected and the activities of HK, PFK, PK and 6-PGD were significantly decreased. The present results suggest that PRL has a direct as well as a synergistic action with androgens on enzymes of EMP and HMP shunt in the prostates of monkeys.

Generation of reduced nicotinamide adenine dinucleotide phosphate mediated by glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase in neutrophils of thoroughbred horses

Em vinte cavalos Puro-Sangue Inglês determinou-se a atividade da glicose-6-fosfato-desidrogenase e da 6-fosfogliconato-desidrogenase de neutrófilos, encontrando-se atividades específicas de 945 ñ 288 mUI mg-1 de proteína e 375 ñ 88 mUI mg-1 de proteína, respectivamente, por minuto a 37§C

Glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase from Lactobacillus casei: responses with different modulators.

Glucose 6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (6PGD) were separated and partially purified from glucose-grown cells of Lactobacillus casei. The enzymes had similar pH optima, thermosensitivity and molecular weights. They had different net charges and their pI values were 5.38 and 4.52, respectively. Histidine, arginine, lysine and cysteine residues were essential for the activity of G6PD, and all the above amino acids with the exception of lysine were required for 6PGD activity. Mg2+ activated 6PGD up to 15 mM concentration, above which it was inhibitory. It had no effect on G6PD activity. G6PD was specific for NADP+, but 6PGD showed some activity with NAD+ as the cofactor, although it was essentially NADP(+)-preferring. Both the enzymes, were inhibited by NADPH. 6PGD was also inhibited by its product, ribulose 5-phosphate. ATP inhibited 6PGD only at subsaturating concentrations of NADP+. The inhibition was sigmoidal in the absence of Mg2+ and hyperbolic in its presence.

Analise enzimatica de 56 amostras de Plasmodium falciparum da bacia Amazonica (Brasil). / Enzymatic analysis of 56 samples of Plasmodium falciparum of Amazonian drainage-basin (Brazil)

Cinquenta e seis amostras de Plasmodium falciparum foram analisadas por eletroforese em acetato de celulose, para seis enzimas: Glucose-fosfato-isomerase, GPI (EC.5.3.1.9); Adenosina-deaminase, ADA (EC. 3.5.4.4); Peptidase, PEP (EC. 3.4.11); Lactato-desidrogenase, LDH (EC. 1.1.1.27); NADP-dependente Glutamato-desidrogenase, GDH (EC. 1.4.1.4) e Fosfato-gluconato-desidrogenase, PGD (EC. 1.1.1.44.3). Os resultados mostraram apenas variacoes para GPI, ADA e PEP. Uma breve comparacao com amostras de outros paises e mencionada