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At least 865 records · Page 48Linked to original sources
PubMed1990

Polyunsaturated and saturated fatty acids-rich diets and immune tissues. 2. Maximal activities of key enzymes of glutaminolysis, glycolysis, pentose-phosphate-pathway and Krebs cycle in thymus, spleen and mesenteric lymph nodes.

It has been widely reported that polyunsaturated fatty acids (PU-FA n-6) in the diet lead to immunosuppression. In the present study, the activity of key enzymes several metabolic pathways were measured in the immune tissues of rats fed polyunsaturated (UC) or saturated fatty (SC) acids-rich diets. The following enzyme activities were measured: hexokinase, citrate synthase, glucose-6-phosphate dehydrogenase, glutaminase and malic enzyme. The metabolism of immune tissues was markedly changed by the fat content of the diet. However, UC diet determined more significant metabolic changes than SC diet.

Animals↗
PubMed1988

Effect of the N-glycosidic bond conformation and modifications in the pentose moiety on the binding of nucleoside ligands to uridine phosphorylase.

Several arabinosyl-, xylosyl-, lyxosyl, 5'-deoxy-, acyclo-, 2,2'-anhydro-, 2,3'-anhydro-2'-deoxy-, 2,5'-anhydro-, 6,5'-cyclo-, and carbocyclic analogues of uridine with various 5-substitutions (fluoro, methyl, bromo, ethyl, benzyl, or benzyloxybenzyl) have been tested and compared with their corresponding ribo- and 2'-deoxyribosides for their potency to inhibit uridine phosphorylase (UrdPase) from both mouse and human livers. The effect of the alpha- and beta-configurations of the glycosidic bond was also tested. Xylo-, lyxo-, 2,3'-anhydro-2'-deoxy-, 6,5'-cyclo-, and carbocyclic uridines did not bind to the enzyme. Ribosides bound better than the corresponding 2'-deoxyribosides, which were better than the 5'-deoxyribosides. 2'-alpha-Deoxyribosides bound to the enzyme, albeit less tightly than the corresponding beta-anomers. The acyclo- and 2,2'-anhydrouridines were all potent inhibitors with the 2,2'-anhydro- derivatives being the most potent. 2,5'-Anhydrouridine bound to UrdPase less effectively than 2,2'-anhydrouridine and acyclouridine. Arabinosyl uracil was at best a very poor inhibitor but binds better if a benzyl group is added at the 5-position of the pyrimidine ring. This binding was enhanced further by adding a 5-benzyloxybenzyl group. A similar enhancement of the binding with increased hydrophobicity at the 5-position of the pyrimidine ring was observed with ribosides, alpha- and beta-anomers of the 2'-deoxyribosides, acyclonucleosides, and 2,2'-anhydronucleosides. The inhibitory potencies of these compounds with UrdPase from human liver roughly parallel those obtained with UrdPase from mouse liver. It is concluded that the presence of a N-glycosidic bond as well as a properly oriented 3'-hydroxyl group are prerequisites for a nucleoside ligand to bind to UrdPase. On the other hand, the presence of a 2'- or 5'-hydroxyl group or an N-glycosidic bond in the beta-configuration enhances but is not essential for binding. Furthermore, the potency of the binding of 2,2'-anhydrouridines (fixed syn-isomers) in contrast to the complete lack of binding of the 6,5'-cyclouridines (fixed anti-isomers) to UrdPase indicates that the binding of ligands to this enzyme is in the syn-conformation around the N-glycosidic bond.

Isomerism↗
PubMedDate not supplied

[Pentose monophoshate pathway and the glutathione system in physiological pregnancy].

At the second and third trimesters of pregnancy an increase in activity of hexokinase, glucose-6-phosphate-(G6PD) and 6-phosphogluconate dehydrogenases (6-PDG) occurred simultaneously with a decrease in concentrations of NADPH2 by 26%, ATP by 17% and an increase in NADP by 10-15% in the pregnant women. Total amount of nicotinamide adenine dinucleotide phosphate was unaltered and constituted 0.082-0.075 mmole/L in erythrocytes from both pregnant and nonpregnant women. Activities of hexose monophosphate and glycolytic pathways of glucose metabolism appear to increase in erythrocytes under conditions of normal pregnancy. Concentration of oxidized glutathione tended to increase in the pregnant women, suggesting a possibility of the hexose monophosphate shunt activation.

Adenosine Triphosphate↗