Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.26 (invertase)
 4,927 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The denaturation of eight purified yeast enzymes, glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase, 3-phosphoglycerate kinase, alcohol dehydrogenase, beta-fructosidase, hexokinase and glucose-6-phosphate isomerase, promoted under controlled conditions by the free fatty acids myristic and oleic, is selective. Glucose-6-phosphate dehydrogenase (D-glucose-6-phosphate:NADP+ 1 oxidoreductase, EC 1.1.1.49) is extremely sensitive to destabilization and was studied in greater detail. Results show that chain length and degree of unsaturation of fatty acids are important to their destabilizing effect, and that ligands of the enzyme can afford protection. The denaturation process results in more than one altered form. These results can be viewed in the perspective of the possibility that amphipathic substances, and in particular free fatty acids, may play a role for enzyme degradation in vivo, by initiating steps of selective denaturation.
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PMID:Selective denaturation of several yeast enzymes by free fatty acids. 35 87

Glycosidases and glycosyltransferases were electrophoresed in the presence of sodium dodecyl sulfate (SDS) in a thin-layer gel supported by a glass plate, treated with the nonionic detergent Triton X-100, and specifically stained for the sugar-releasing activity of these enzymes. Staining is based on conversion of monosugars or a sugar phosphate to glucose-6-phosphate by the appropriate intermediary enzymes, reduction of NADP+ to NADPH, and accumulation of reduced Nitroblue Tetrazolium in the gel. Among the enzymes tested, alpha-glucosidase, beta-glucosidase and beta-mannosidase could not be renatured, whereas beta-fructofuranosidase and alpha-mannosidase could be renatured unless heated before electrophoresis. Sucrose phosphorylase, glucosyltransferase and fructosyltransferase, which are single-peptide proteins with no cystine bond, could be renatured even after pretreatment with SDS and/or mercaptoethanol at 100 degrees C for 10 min. However, exclusive heating remarkably decreased the activities of these enzymes. Two-dimensional separation of the five renaturable enzymes was done in a single thin-layer gel, using SDS-electrophoresis in the first dimension and isoelectric focusing in the second dimension.
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PMID:Renaturation and activity staining of glycosidases and glycosyltransferases in gels after sodium dodecyl sulfate-electrophoresis. 752 70

The enzymatic conversion of sugars to hydrogen could be a promising method for alternative fuel production. Maple tree sap is a source of environmental sugar (e.g., sucrose) that has the potential to be converted into hydrogen using the enzymes invertase, glucose dehydrogenase (GDH), hydrogenase, and glucose isomerase (GI) and the cofactor NADP+/NADPH. The kinetics of hydrogen production have been studied, and optimal conditions for hydrogen production are described. At low initial sucrose concentrations, in the absence of glucose isomerase, stoichiometric yields of 1 mol of H2/mol of sucrose were achieved. At higher sucrose concentrations, the yield of hydrogen declined so that at an initial sucrose concentration of 292 mM only 7% yield of hydrogen was obtained. The reason for this low yield was studied and shown not to be caused by enzyme inactivation or a pH drop during the reaction but due to an instability of the cofactor NADP+. Although gluconic acid inhibited both NADPH production and oxidation by GDH and hydrogenase, respectively, it was not the major cause of NADP+ instability. Fructose was also shown to be converted to hydrogen if GI was present in the reaction mixture. Also, by starting with sucrose, 1. 34 mol of H2/mol of sucrose was obtained if GI was present in the reaction mixture.
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PMID:Enzymatic conversion of sucrose to hydrogen 984 53