IV-Ethylmaleimide

The following abbreviations have been employed FDNB, 2,4-fluorodinitro-benzene F6P, fructose 6-phosphate FDP, fructose 1,6-diphosphate FDPase, fructose-1,6-diphosphatase NEM, iV-ethylmaleimide PFK, phosphofructokinase PLP, pyridoxal phosphate SDP, sedoheptulose 1,7-diphosphate SDS, sodium dodecyl sulfate. 

D-lactate dehydrogenase and, 271 lipoamide dehydrogenase and, 126 NADH dehydrogenase and, 206 succinate dehydrogenase and, 247 thioredoxin reductase and, 147, 148 Ethyl hydrogen peroxide, catalase and, 391-392, 395 iV-Ethylmaleimide c> tochrome b, reductase and, 163,... 

Solnble iV-ethylmaleimide-sensitive fnsion (NSF A -ethylmaleimide-sensitive factor) protein attachment protein receptors can be either R-SNAREs or Q-SNARES depending on sequence homologies SNARE motif Small nucleolar RNA Single nucleotide polymorphism Small nuclear RNA... 

TABLE 3. Rate constants for the Diels-Alder reaction of anthracene and IV-ethylmaleimide in different solvents... 

Studies of highly purified preparations of LCAT have provided important information about its properties and the factors that influence its activity. An acidic glycoprotein of 60-65 kDa, it contains a variable number of sialic acid residues [57]. Sulfhydryl reagents such as iV-ethylmaleimide inhibit the enzyme, suggesting that one or more free sulfhydryl groups are required for its activity. 

The NADP-specific enzyme of Neurospora contains a lysine residue with pK = 7.6 at 34°, which reacts with pyridoxal phosphate or iV-ethylmaleimide to yield an inactive enzyme (65). The heat of ionization of the -amino group as judged by its reaction with A -ethylmale-imide is 12,6 2.0 kcal/mole. The labeled residue, Lys-113, is in a homologous sequence with that of the vertebrate enzymes (Fig. 5). 

Briefly wash the printed slide with water and immerse in water containing 1% IV-ethylmaleimide with gentle shaking for 15 min at room temperature to remove unreacted thiol groups (see Note 13). 

The actual phosphorylation step is the transfer of the ATP y-phosphate to an aspartyl- -carboxyl group [29,30] with release of ADP (Fig. 1). Some authors [31] assume an intermediate, in which ADP is still bound to the phosphoenzyme, which is feasible in view of the reversibility of the reaction. Under normal conditions, however, the phosphorylated intermediate does not react with ADP, unless the bound Mg " is replaced by Ca [32,33], the enzyme has been pretreated with the sulfhydryl reagent iV-ethylmaleimide [34] or has undergone limited proteolysis in the presence of Na" " [35]. In all of these conditions the overall Na-K ATPase activity is inhibited, apparently through interference with a conformational transition from an ADP-sensitive to an ADP-insensitive phosphointermediate, the third step in the reaction mechanism. 

Diels-Alder reaction, catalyzes the cycloaddition between terachlorothiophene dioxide and iV-ethylmaleimide. This reaction occurs via a bridged sulfone intermediate forming tetrachlorophthalimide through sulfone elimination and spontaneously oxidative aromatization (Fig. 3B). This catalyst displays an effective molarity (EM=kca/ku cat) of 1000 M, which is extremely efficient for a bimolecular reaction catalyzed by an antibody. The hapten used to elicit this antibody is a derivative of endo hexachloronor-bomene. which is a shape mimic of the transition state. Because it has less structural similarity to the aromatic product, product inhibition in the lE9-catalyzed reaction is avoided. 

In an attempt to mimic membrane fusion events, the Kros lab has constructed a simplified peptide-based model of the SNARE (soluble NSF (iV-ethylmaleimide sensitive factor) attachment protein receptor) proteins intrinsic to this... 

Paper chromatography offers possibilities for overcoming some of these difficulties. The demonstration by Hanes, Hird, and Isherwood (1), that sulfhydryl peptides can be chromatographed successfully if first stabilized by coupling with iV-ethylmaleimide eliminated a major obstacle, the tendency of SH compounds to streak on the paper. 

Fleming, I.N. and Yeaman S.J. (1995) Purification and characterisation of iV-ethylmaleimide-insensitive phosphatidic acid phosphohydrolase (PAP2) from rat hver. Biochemical Journal 308,983-989... 

One of these compounds, 9-(p-bromoacetamidobenzyl) adenine, has been used for labeling the amino acid residues of the active site. In fact the functional groups of adenosine deaminase are particularly unreac-tive. The sulfhydryl groups present in the catalytic site react with p-mercuribenzoate and phenylmercuriacetate, but not with haloacetates, haloacetamides, iV-ethylmaleimide, or 5,5 -dithiobis-(2-nitrobenzoic acid). The enzyme is inactivated by l-fluoro-2,4-dinitrobenzene and by haloacetates at pH values over 7.5 and 9.0, respectively more than one lysine residue is modified under these conditions. ... 

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