Kinetics and Thermodynamics of the Interchange of the Morpheein Forms of Human Porphobilinogen Synthase†

Biochemistry ◽  
2008 ◽  
Vol 47 (10) ◽  
pp. 3245-3257 ◽  
Author(s):  
Trevor Selwood ◽  
Lei Tang ◽  
Sarah H. Lawrence ◽  
Yana Anokhina ◽  
Eileen K. Jaffe
Keyword(s):  
Kinetics And Thermodynamics ◽  
Porphobilinogen Synthase

Adsorption of safranine T from aqueous medium by nano mesoporous MCM-41: adsorption equilibrium, kinetics, and thermodynamics

2020 ◽  
Vol 10 ◽  
Author(s):  
Xiao-Dong Li ◽  
Qing-Zhou Zhai
Keyword(s):  
Electron Microscopy ◽  
Ph Value ◽  
Particle Diameter ◽  
Spherical Particles ◽  
Practical Significance ◽  
Average Particle ◽  
Average Pore ◽  
Kinetics And Thermodynamics ◽  
Safranine T ◽  
Mcm 41

Introduction: In industrial production, a small amount of saffron T emissions will cause increase of water color and increase of chemical oxygen consumption, so study of the decolorization of saffron T wastewater has an important practical significance. Methods: MCM (Mobil Composition of Matter)-41 molecular sieve was synthesized by hydrothermal method. Power Xray diffraction and scanning electron microscopy were used to characterize the sample. Safranine T dye was adsorbed from water by the MCM-41 prepared. Kinetics and thermodynamics of the adsorption were studied. Results: The MCM-41 sample presented spherical particles and regular. The BET (Brunner-Emmett-Teller) specific surface area of the sample determined by 77 K low temperature nitrogen adsorption-desorption isotherm was 932 m2 /g. Its average particle diameter was 110 nm. TEM (transmission electron microscopy) results showed that the sample structure presented a honeycomb pore structure and the average pore diameter was 3.0 nm. The results showed that when room temperature was 20 ± 1 ℃, adsorbate safranine T: adsorbent MCM-41 = 20 : 1，the optimum pH value of adsorption was 4.0 and contact time was 20 min, the adsorption rate reached 98.29% and the adsorption capacity was 19.66 mg/g. The entropy change and enthalpy change of the adsorption system are respectively ΔS0 = 157.5 J/(mol·K); ΔH0 = 21.544 kJ/mol. When temperature was 277.15, 293.15, 303.15 K，the free energy change was respectively △G1 0 = -22.107 kJ/mol, △G2 0 = -24.627 kJ/mol, △G3 0 = -26.202 kJ/mol. Conclusion: The adsorption of safranine T by MCM-41 belongs to a pseudo-second-order adsorption. This adsorption accords with the Freundlich equation and belongs to a heterogeneous adsorption. The adsorption is an endothermic reaction of entropy increase, being spontaneous.

scholarly journals Mechanism of porphobilinogen synthase. Requirement of Zn2+ for enzyme activity.

1980 ◽  
Vol 255 (5) ◽  
pp. 2030-2035
Author(s):  
D.R. Bevan ◽  
P. Bodlaender ◽  
D. Shemin
Keyword(s):  
Enzyme Activity ◽  
Porphobilinogen Synthase

scholarly journals Kinetics and thermodynamics of oxygen, CO, and azide binding by the subcomponents of soybean leghemoglobin.

1990 ◽  
Vol 265 (32) ◽  
pp. 19588-19593
Author(s):  
K D Martin ◽  
L Saari ◽  
G X Wang ◽  
T Wang ◽  
L J Parkhurst ◽  
...  
Keyword(s):  
Kinetics And Thermodynamics ◽  
Azide Binding ◽  
Soybean Leghemoglobin
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