- Versatile small molecule kinase assay through real-time, ratiometric fluorescence changes based on a pyrene-DPA-Zn2+complex
-
A real-time kinase assay method based on a ratiometric fluorescence probe that can be applied to various small-molecule kinases is described herein. The probe can trace the reversible interchange of ATP and ADP, which is a common phenomenon in most small-molecule kinase reactions, by a ratiometric fluorescence change. This property facilitates the monitoring of phosphorylation and dephosphorylation in small-molecule kinases, whereas most of the existing methods focus on one of these reactions. To prove the applicability of this method for small-molecule kinase assays, hexokinase and creatine kinase, which phosphorylate and dephosphorylate substrates, respectively, were analyzed. The ratiometric fluorescence change was correlated with the enzyme activity, and the inhibition efficiencies of the well-known inhibitors,N-benzoyl-d-glucosamine and iodoacetamide, were also monitored. Notably, the change in fluorescence can be observed with a simple light source by the naked eye.
- Kim, Jihoon,Oh, Jinyoung,Han, Min Su
-
p. 10375 - 10380
(2021/03/23)
-
- A novel, cupin-type phosphoglucose isomerase in Escherichia coli
-
Background: Escherichia coli cells contain a homolog of presumed 5-keto-4-deoxyuronate isomerase (KduI) from pectin-degrading soil bacteria, but the catalytic activity of the E. coli protein (o-KduI) was never demonstrated. Methods: The known three-dimensional structure of E. coli o-KduI was compared with the available structures of sugar-converting enzymes. Based on the results of this analysis, sugar isomerization activity of recombinant o-KduI was tested against a panel of D-sugars and their derivatives. Results: The three-dimensional structure of o-KduI exhibits a close similarity with Pyrococcus furiosus cupin-type phosphoglucose isomerase. In accordance with this similarity, o-KduI was found to catalyze interconversion of glucose-6-phosphate and fructose-6-phosphate and, less efficiently, conversion of glucuronate to fructuronate. o-KduI was hexameric in crystals but represented a mixture of inactive hexamers and active dimers in solution and contained a tightly bound Zn2+ ion. Dilution, substrate binding and Zn2+ removal shifted the hexamer ? dimer equilibrium to the dimers. Conclusions: Our findings identify o-KduI as a novel phosphosugar isomerase in E. coli, whose activity may be regulated by changes in oligomeric structure. General Significance: More than 5700 protein sequences are annotated as KduI, but their enzymatic activity has not been directly demonstrated. E. coli o-KduI is the first characterized member of this group, and its enzymatic activity was found to be different from the predicted activity.
- Baykov, Alexander A.,Kolomijtseva, Galina Ya.,Kurilova, Svetlana A.,Nazarova, Tatiana I.,Petukhova, Anastasia F.,Rodina, Elena V.,Vorobjeva, Natalia N.
-
-
- Pyrazine-derived disulfide-reducing agent for chemical biology
-
For fifty years, dithiothreitol (DTT) has been the preferred reagent for the reduction of disulfide bonds in proteins and other biomolecules. Herein we report on the synthesis and characterization of 2,3-bis(mercaptomethyl)pyrazine (BMMP), a readily accessible disulfide-reducing agent with reactivity under biological conditions that is markedly superior to DTT and other known reagents. This journal is the Partner Organisations 2014.
- Lukesh, John C.,Wallin, Kelly K.,Raines, Ronald T.
-
supporting information
p. 9591 - 9594
(2014/08/18)
-
- Aldose-6-phosphate reductase from apple leaves: Importance of the quaternary structure for enzyme activity
-
Aldose-6-phosphate reductase (A6PRase) is a key enzyme for glucitol biosynthesis in plants from the Rosaceae family. To gain on molecular tools for enzymological studies, we developed an accurate system for the heterologous expression of A6PRase from apple leaves. The recombinant enzyme was expressed with a His-tag alternatively placed in the N- or C-terminus, thus allowing the one-step protein purification by immobilized metal affinity chromatography. Both, the N- and the C-term tagged enzymes exhibited similar affinity toward substrates, although the kcat of the latter enzyme was 80-fold lower than that having the His-tag in the N-term. Gel filtration chromatography showed different oligomeric structures arranged by the N- (dimer) and the C-term (monomer) tagged enzymes. These results, reinforced by homology modeling studies, point out the relevance of the C-term domain in the structure of A6PRase to conform an enzyme having optimal specific activity and the proper quaternary structure.
- Figueroa, Carlos M.,Iglesias, Alberto A.
-
experimental part
p. 81 - 88
(2010/12/25)
-
- Reversible and in Situ Formation of Organic Arsenates and Vanadates as Organic Phosphate Mimics in Enzymatic Reactions: Mechanistic Investigation of Aldol Reactions and Synthetic Applications
-
A synthetic strategy is developed that uses organic phosphate utilizing enzymes as catalysts and a mixture of an organic alcohol and inorganic arsenate or vanadate to replace the organic phosphate substrate.In this process, inorganic arsenate or vanadate reacts with the alcohol reversibly in situ to form a mixture of esters, one of which is accepted by the enzyme as a substrate.Examples of the utility of this approach are demonstrated in enzymatic aldol condensations catalyzed by fructose-1,6-diphosphate aldolase, fuculose-1-phosphate aldolase, and rhamnulose-1-phosphate aldolase with a mixture of dihydroxyacetone and inorganic arsenate as substrate.Several uncommon sugars and deoxy sugars are prepared on 5-17-mmol scales.Mechanistic studies on an aldol reaction indicate that the redox reaction between dihydroxyacetone and inorganic vanadate prohibits the use of such a mixture to replace dihydroxyacetone phosphate in enzymatic aldol condensations.
- Drueckhammer, Dale G.,Durrwachter, J. Robert,Pederson, Richard L.,Crans, Debbie C.,Daniels, Lacy,Wong, Chi-Huey
-
-
- Pharmaceutical salts of 4-(9-acridinyl-amino) methanesulfon-m-anisidide
-
Pharmaceutical salts of 4'-(9-acridinylamino)--methanesulfon-m-anisidide, methods for their preparation and use of said salts in the form of pharmaceutical compositions as antineoplastic agents.
- -
-
-
- Pharmaceutical salts of 4'-(9-acridinylamino)-methanesulfon-m-anisidide
-
Pharmaceutical salts of 4'-(9-acridinylamino)-methanesulfon-m-anisidide, methods for their preparation and use of said salts in the form of pharmaceutical compositions as antineoplastic agents.
- -
-
-