Báo cáo khoa học: Catalytic reaction mechanism of Pseudomonas stutzeri L-rhamnose isomerase deduced from X-ray structures doc

... a-helices. Residues involved in binding of the cofactor ThDP are located at the C-terminal ends of the b-strands of Dom-c (diphosphates and Mg 2+ ) and of Dom-a¢ of a neighbouring subunit (pyrimidine moiety). ... and Dom-c of subunit A with their counterparts in subunit B. It is stabilized by a large number of hydrogen bonds. The weaker contact results from an association of...

Ngày tải lên: 07/03/2014, 12:20

... use of citrate synthase from pig heart. Oxaloacetate was continuously provided from malate by use of NAD + and malate dehydrogenase (MDH) from pig h eart. A typical a ssay in a final volume of ... propionyl- CoA a nd acetyl-CoA. In the presence of both thioesters one might expect an accumulation of succinyl-CoA in t he cell and a deadlock of further reactions of the citric...

Ngày tải lên: 19/02/2014, 16:20

... that less of the enzyme is involved in productive enzyme–NADPH complexes involved in the overall rate limiting step of the reaction. The effects of zinc on the binding of reduced cofac- tor to ... the inhibitory effect of zinc. Structures of various states of the enzyme have shown that both regions are heavily involved in the con- formational changes associated with catalyt...

Ngày tải lên: 05/03/2014, 23:20

... characteristics of the branched-chain mechanism is the multiplication of active or catalytic centers in the time course of the reactions, a feature that makes these processes similar to the autocatalytic reactions ... FEBS consistent with the mechanism of branched-chain reactions. Employing the theory of branched-chain reactions will greatly benefit our understanding of the p...

Ngày tải lên: 07/03/2014, 10:20

... are probably required in such a mechanism for binding and sliding of the substrate chain. Barley AMY1 and AMY2 have a degree of multiple attack toward amylose of two (B. Kramhøft and B. Svensson, unpublished ... Svensson, unpublished data). The goal of the present work is to characterize further the AMY1 and AMY2 function toward soluble sub- strates. The kinetics of hydrolysis of...

Ngày tải lên: 08/03/2014, 08:20

... phosphorylation of R-Smad proteins (a), the for- mation of R-Smad(P)–Smad4 complexes (b), transloca- tion of these complexes to the nucleus (c), and their Fig. 7. Mechanisms of short-term and ... Using adenoviral overexpression of Smad2 ⁄ 3, we studied the role of Smad proteins in regulation of the RhoA ⁄ B genes, activation of these small GTPases and the induction of actin...

Ngày tải lên: 16/03/2014, 06:20

... organization of this enzyme is substantially different from that of the spinach enzyme with the active site constructed from two monomers of a dode- camer. In contrast, the active site of spinach ... the reductase reaction. The reverse of the iso- merase reaction is thermodynamically favoured by the near irreversi- bility of the conversion of the 2-ketoacid to TS2. Howeve...

Ngày tải lên: 16/03/2014, 18:20

... dissoci- ation of Arenicola Hb at alkaline pH or in the presence of urea, induces fragmentation of the linker chains, probably as a result of their oxidation in the presence of free hemin. The effect of ... indicating possible degradation of the protein. Kinetic of dissociation of Arenicola Hb Dissociation of Arenicola Hb followed by gel filtration The extent of dissociat...

Ngày tải lên: 23/03/2014, 10:21

... paper. The enzymes of the three groups are thought to have similar structures and the same catalytic mechanism is involved, because their amino acid sequences have a high degree of similarity [3,4]. ... analysis of avian farnesyl diphosphate synthase (FPS) revealed that the homodimeric enzyme consists almost entirely of a-helices, some of which constitute a reaction cavity i...

Ngày tải lên: 23/03/2014, 17:21

... resulting from acid hydrolysis of UDP- glucuronate, was measured. This value was subtracted from those found in the presence of liver extract. Note that the scale of the ordinate in Fig. 2B differs from ... was independent of glucuronate 1-phosphate formation. In the presence of ATP-Mg, the rate of hydrolysis of 0.5 mm glucuronate 1-phosphate amounted to 0.04 nmolÆmin )1 Æ...

Ngày tải lên: 19/02/2014, 07:20