Effect of Metal Ions and Adenylylation State on the Energetics of the E. Coli Glutamine Synthetase Reaction

Author(s):  
Lynn M. Abell ◽  
Joseph J. Villafranca
2002 ◽  
Vol 42 (supplement2) ◽  
pp. S138
Author(s):  
T. Suzuki ◽  
A. Kashiwagi ◽  
K. Mori ◽  
I. Urabe ◽  
T. Yomo

1997 ◽  
Vol 16 (5-6) ◽  
pp. 721-725 ◽  
Author(s):  
Jens M. Warneckes ◽  
Christopher J. Green ◽  
Roland K. Hartmann
Keyword(s):  
Rnase P ◽  

1973 ◽  
Vol 131 (4) ◽  
pp. 833-841 ◽  
Author(s):  
Donald Stribling ◽  
Richard N. Perham

Two fructose diphosphate aldolases (EC 4.1.2.13) were detected in extracts of Escherichia coli (Crookes' strain) grown on pyruvate or lactate. The two enzymes can be resolved by chromatography on DEAE-cellulose at pH7.5, or by gel filtration on Sephadex G-200, and both have been obtained in a pure state. One is a typical bacterial aldolase (class II) in that it is strongly inhibited by metal-chelating agents and is reactivated by bivalent metal ions, e.g. Ca2+, Zn2+. It is a dimer with a molecular weight of approx. 70000, and the Km value for fructose diphosphate is about 0.85mm. The other aldolase is not dependent on metal ions for its activity, but is inhibited by reduction with NaBH4 in the presence of substrate. The Km value for fructose diphosphate is about 20μm (although the Lineweaver–Burk plot is not linear) and the enzyme is probably a tetramer with molecular weight approx. 140000. It has been crystallized. On the basis of these properties it is tentatively assigned to class I. The appearance of a class I aldolase in bacteria was unexpected, and its synthesis in E. coli is apparently favoured by conditions of gluconeogenesis. Only aldolase of class II was found in E. coli that had been grown on glucose. The significance of these results for the evolution of fructose diphosphate aldolases is briefly discussed.


Biochemistry ◽  
1988 ◽  
Vol 27 (1) ◽  
pp. 165-170 ◽  
Author(s):  
Charles D. Eads ◽  
Russell LoBrutto ◽  
Alok Kumar ◽  
Joseph J. Villafranca

2020 ◽  
Vol 11 (1) ◽  
pp. 7393-7399

In this work, we synthesized two tetraaza [N4] macrocyclic complexes of FeIII and CoII metal ions. The synthesized macrocyclic complexes were fully characterized by using various analytical techniques IR, UV-Vis, and MS. The spectral analysis indicated an octahedral geometry for both macrocyclic complexes. The electrochemical behavior was carried out using cyclic voltammetry on the Pt dish (0.031 cm2) electrode. The complexes were shown to have unusual oxidation states for the metal ions. The “heterogeneous electron transfer rate constant” (Ko) was also calculated using “Nicholson and Kochi’s method” and observed in the order: KoCoII > KoFeIII. The antimicrobial activities of two complexes were computed against E. coli, P. aeruginosa, B. cereus, S. aureus, whereas antifungal activities against C. Albicans and were contrasted with the standard drug “Gentamycin”.


2021 ◽  
Vol 19 (3) ◽  
pp. 509-517
Author(s):  
Nguyen Khanh Hoang Viet ◽  
Ha Thi Thuy Hoa ◽  
Truong Nam Hai ◽  
Do Thi Huyen

A gene coding for GH5 endoglucanase exploited from metagnomic DNA data of bacteria in Vietnamese goats’ rumen was modularity structure including a catalytic module, a fibronectin-3 like module and an X module. The recombinant enzyme was sucessfully expressed in E. coli and purified.  To study the effect of some metal ions and chemicals on enzyme activity, in this study, we used some tools including Swiss-Prot, ProFunc, COFACTOR for prediction of enzyme structure and ligands interaction. The obtained results indicated that the most similar structure with enzyme had two conserved residues (Asp-190 và Asp-192) linked with Mn2+ within a radius of ~ 3.5 Å from the center of ion Mn2+ and enzyme molecule contained a disulphide bond. Experimental results for essessment of the effect of some metal ions (Ca2 +, Mn2 +, Mg2+, Ni2+, K+, Co2+, Cu2+, Zn2+, Fe3+) at the final concentration of 10 mM and of six common chemicals including SDS (1%), urea (1 µM), 2-mercaptoethanol (1 µM), EDTA (1 µM), tween 80 (1mM), triton X-100 (1 µM) showed that only Mn2+ increased enzyme activity slightly at concentration of 10 mM and two times at the concentration of 40 mM Mn2+. The Mn2+ has been identified as a specific binding agent may increase the stability and activity of endoglucanase GH5.


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