scholarly journals Woodward's reagent K inactivation of Escherichia coli L-threonine dehydrogenase: Increased absorbance at 340-350 nm is due to modification of cysteine and histidine residues, not aspartate or glutamate carboxyl groups

1996 ◽  
Vol 5 (2) ◽  
pp. 382-390 ◽  
Author(s):  
Adam R. Johnson ◽  
Eugene E. Dekker
Keyword(s):  
Escherichia Coli ◽  
Carboxyl Groups ◽  
Histidine Residues ◽  
Threonine Dehydrogenase ◽  
Woodward’S Reagent K

scholarly journals Characterization of site-directed mutants in the lac permease of Escherichia coli. 1. Replacement of histidine residues

Biochemistry ◽  
1989 ◽  
Vol 28 (6) ◽  
pp. 2525-2533 ◽  
Author(s):  
Irene B. Puttner ◽  
Hemanta K. Sarkar ◽  
Etana Padan ◽  
Julius S. Lolkema ◽  
H. Ronald Kaback
Keyword(s):  
Escherichia Coli ◽  
Histidine Residues

The melibiose/Na + symporter of Escherichia coli : kinetic and molecular properties

1990 ◽  
Vol 326 (1236) ◽  
pp. 411-423 ◽  
Keyword(s):  
Escherichia Coli ◽  
Complex Cation ◽  
Expression System ◽  
Binding Activity ◽  
Site Directed Mutagenesis ◽  
Coupling Mechanism ◽  
Facilitated Diffusion ◽  
Histidine Residues ◽  
Sugar Binding ◽  
Dependent Transport

The role of the co-transported cation in the coupling mechanism of the melibiose permease of Escherichia coli has been investigated by analysing its sugar-binding activity, facilitated diffusion reactions and energy-dependent transport reactions catalysed by the carrier functioning either as an H + , Na + or Li + -sugar symporter. The results suggest that the coupling cation not only acts as an activator for sugar-binding on the carrier but also regulates the rate of dissociation of the co-substrates in the cytoplasm by controlling the stability of the ternary complex cation-sugar—carrier facing the cell interior. Furthermore, there is some evidence that the membrane potential enhances the rate of symport activity by increasing the rate of dissociation of the co-substrates from the carrier in the cellular compartment. Identification of the melibiose permease as a membrane protein of 39 kDa by using a T7 RNA polymerase/promoter expression system is described. Site-directed mutagenesis has been used to replace individual carrier histidine residues by arginine to probe the functional contribution of each of the seven histidine residues to the symport mechanism. Only substitution of arginine for His94 greatly interferes with the carrier function. It is finally shown that mutations affecting the glutamate residue in position 361 inactivate translocation of the co-substrates but not their recognition by the permease.

Interaction between the carboxyl groups of Asp127 and Asp129 in the active site of Escherichia coli phosphofructokinase

1992 ◽  
Vol 207 (3) ◽  
pp. 1109-1114 ◽  
Author(s):  
Romuald LAINE ◽  
Dominique DEVILLE-BONNE ◽  
Isabelle AUZAT ◽  
Jean-Renaud GAREL
Keyword(s):  
Escherichia Coli ◽  
Active Site ◽  
Carboxyl Groups

scholarly journals Role of threonine dehydrogenase in Escherichia coli threonine degradation.

1977 ◽  
Vol 132 (2) ◽  
pp. 385-391 ◽  
Author(s):  
R Potter ◽  
V Kapoor ◽  
E B Newman
Keyword(s):  
Escherichia Coli ◽  
Threonine Dehydrogenase

Yeast enolase carboxyl modification using Woodward's reagent K

1986 ◽  
Vol 64 (10) ◽  
pp. 970-975 ◽  
Author(s):  
Uma Sinha ◽  
John M. Brewer
Keyword(s):  
Metal Ion ◽  
Carboxyl Groups ◽  
Tryptic Peptides ◽  
Woodward’S Reagent K ◽  
Carboxyl Modification ◽  
Yeast Enolase

Yeast enolase is inactivated by Woodward's reagent K. Substantial protection is afforded by binding of 1 mol of "conformational" metal ion/subunit. Inactivation is correlated with modification of 13 carboxyl groups/subunit in the absence of conformational metal ion and 17 in its presence. Ten tryptic peptides labeled by Woodward's reagent K can be isolated, mostly from the C-terminal half of the protein. The changes in reactivity of these peptides produced by conformational metal ion suggest direct coordination to Glu-181 together with a contraction of the protein.

Site-specific mutagenesis of Escherichia coli asparaginase II. None of the three histidine residues is required for catalysis

1992 ◽  
Vol 208 (2) ◽  
pp. 475-480 ◽  
Author(s):  
Andreas WEHNER ◽  
Etti HARMS ◽  
Michael P. JENNINGS ◽  
Ifor R. BEACHAM ◽  
Christian DERST ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Site Specific ◽  
Histidine Residues

scholarly journals Modification of uridine phosphorylase from Escherichia coli by diethyl pyrocarbonate. Evidence for a histidine residue in the active site of the enzyme

1990 ◽  
Vol 270 (2) ◽  
pp. 319-323 ◽  
Author(s):  
A K Drabikowska ◽  
G Woźniak
Keyword(s):  
Escherichia Coli ◽  
Enzyme Activity ◽  
Active Site ◽  
Order Rate Constant ◽  
Enzymic Activity ◽  
Histidine Residue ◽  
Uridine Phosphorylase ◽  
High Concentration ◽  
Histidine Residues ◽  
Diethyl Pyrocarbonate

Uridine phosphorylase from Escherichia coli is inactivated by diethyl pyrocarbonate at pH 7.1 and 10 degrees C with a second-order rate constant of 840 M-1.min-1. The rate of inactivation increases with pH, suggesting participation of an amino acid residue with pK 6.6. Hydroxylamine added to the inactivated enzyme restores the activity. Three histidine residues per enzyme subunit are modified by diethyl pyrocarbonate. Kinetic and statistical analyses of the residual enzymic activity, as well as the number of modified histidine residues, indicate that, among the three modifiable residues, only one is essential for enzyme activity. The reactivity of this histidine residue exceeded 10-fold the reactivity of the other two residues. Uridine, though at high concentration, protects the enzyme against inactivation and the very reactive histidine residue against modification. Thus it may be concluded that uridine phosphorylase contains only one histidine residue in each of its six subunits that is essential for enzyme activity.

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