scholarly journals Thermodynamic Activity-Based Michaelis Constants

2019 ◽  
Author(s):  
Anton Wangler ◽  
Mark Jonathan Bunse ◽  
Gabriele Sadowski ◽  
Christoph Held
Keyword(s):  
Thermodynamic Activity ◽  
Michaelis Constants

Prediction and Experimental Validation of Co-Solvent Influence on Michaelis Constants: A Thermodynamic Activity-Based Approach

2018 ◽  
Vol 24 (61) ◽  
pp. 16418-16425 ◽  
Author(s):  
Anton Wangler ◽  
Dominik Böttcher ◽  
Aline Hüser ◽  
Gabriele Sadowski ◽  
Christoph Held
Keyword(s):  
Experimental Validation ◽  
Thermodynamic Activity ◽  
Solvent Influence ◽  
Michaelis Constants

Thermodynamic activity and electron energy spectrum of metallic solutions

2014 ◽  
Vol 44 (2) ◽  
pp. 90-95
Author(s):  
I. F. Selyanin ◽  
V. B. Deev ◽  
A. I. Kutsenko ◽  
A. A. Kutsenko ◽  
O. G. Prikhod’ko
Keyword(s):  
Energy Spectrum ◽  
Electron Energy ◽  
Thermodynamic Activity ◽  
Electron Energy Spectrum

scholarly journals Aspartate aminotransferase. The effects of ionic concentration on kinetic constants of both isoenzymes

1968 ◽  
Vol 106 (3) ◽  
pp. 581-586 ◽  
Author(s):  
T. R. C. Boyde
Keyword(s):  
Aspartate Aminotransferase ◽  
Specific Effect ◽  
Ionic Concentration ◽  
Phosphate Concentration ◽  
Kinetic Constants ◽  
Sharp Minimum ◽  
Ionic Concentrations ◽  
Michaelis Constants ◽  
Added Salt

1. The Michaelis constants for both isoenzymes for both substrates depend strongly on ionic concentration, being approximately proportional to phosphate concentration over considerable ranges. This is probably an effect of anions only. 2. In the absence of added salt, Km (2-oxoglutarate) (anionic isoenzyme) is so small as to be indeterminate. 3. Km (l-aspartate) (anionic isoenzyme) passes through a sharp minimum at about 3·3mm-phosphate. It is not clear whether this is a specific effect of phosphate. 4. Both substrates are inhibitory at sufficiently low ionic concentrations. 5. A modified graphical procedure is described for the derivation of the kinetic constants.

scholarly journals Dextran strongly increases the Michaelis constants of oxidative phosphorylation and of mitochondrial creatine kinase in heart mitochondria

1998 ◽  
Vol 254 (1) ◽  
pp. 172-180 ◽  
Author(s):  
Frank Norbert Gellerich ◽  
Fanny Dorine Laterveer ◽  
Bernard Korzeniewski ◽  
Stephan Zierz ◽  
Klaas Nicolay
Keyword(s):  
Creatine Kinase ◽  
Oxidative Phosphorylation ◽  
Heart Mitochondria ◽  
Mitochondrial Creatine Kinase ◽  
Michaelis Constants

scholarly journals Mucin biosynthesis. Properties of a bovine tracheal mucin β-6-N-acetylglucosaminyltransferase

1985 ◽  
Vol 227 (2) ◽  
pp. 405-412 ◽  
Author(s):  
P W Cheng ◽  
W E Wingert ◽  
M R Little ◽  
R Wei
Keyword(s):  
Enzyme Activity ◽  
Freezing Point ◽  
Cetylpyridinium Chloride ◽  
Sodium Dodecyl ◽  
Sodium Deoxycholate ◽  
Gas Chromatography Mass Spectrometry ◽  
Tween 20 ◽  
Group A ◽  
Michaelis Constants ◽  
Triton X

We have characterized a bovine tracheal mucin beta-6-N-acetylglucosaminyltransferase that catalyses the transfer of N-acetylglucosamine from UDP-N-acetylglucosamine to the C-6 of the N-acetylgalactosamine residue of galactosyl-β 1→3-N-acetylgalactosamine. Optimal enzyme activity was obtained between pH 7.5-8.5, at 5mM-MnCl2, and at 0.06-0.08% (v/v) Triton X-100 (or Nonidet P-40), or 0.5-5.0% (v/v) Tween 20. Ba2+, Mg2+ and Ca2+ could partially replace Mn2+, but Co2+, Fe2+, Cd2+ and Zn2+ could not. Sodium dodecyl sulphate, cetylpyridinium chloride, sodium deoxycholate, octyl beta-D-glucoside, digitonin and alkyl alcohols were less effective in enhancing enzyme activity, and dimethyl sulphoxide was ineffective. The apparent Michaelis constants were 1.25 mM for UDP-N-acetylglucosamine, 0.94-3.34 mM for freezing-point-depressing glycoprotein and 0.19 mM for periodate-treated blood-group-A porcine submaxillary mucin. Asialo ovine submaxillary mucin could not serve as the glycosyl acceptor. The structure of the 14C-labelled oligosaccharide obtained by alkaline-borohydride treatment of the product was identified as Gal beta 1→3(Glc-NAc beta 1→6)N-acetylgalactosaminitol by beta-hexosaminidase treatment, gas chromatography-mass spectrometry and 1H-n.m.r. (270 MHz) analysis. The enzyme is important in the regulation of mucin oligosaccharide biosynthesis.

Thermodynamic activity of solute in multicomponent alloy from first-principles: Excess Mg in Mg3(Sb1-Bi )2 as an example

Calphad ◽  
2021 ◽  
Vol 74 ◽  
pp. 102318
Author(s):  
Erting Dong ◽  
Shihua Tan ◽  
Jiong Wang ◽  
Weishu Liu ◽  
Wenqing Zhang
Keyword(s):  
First Principles ◽  
Thermodynamic Activity ◽  
Multicomponent Alloy ◽  
Excess Mg

Osmotic stability of red cells in renal circulation requires rapid urea transport

1988 ◽  
Vol 254 (5) ◽  
pp. C669-C674 ◽  
Author(s):  
R. I. Macey ◽  
L. W. Yousef
Keyword(s):  
Lipid Bilayers ◽  
Physiological Role ◽  
Renal Medulla ◽  
Red Cells ◽  
Facilitated Diffusion ◽  
Urea Transport ◽  
Permeability Characteristics ◽  
Cortex Cell ◽  
Cell Stability ◽  
Michaelis Constants

Urea transport by the human erythrocyte occurs via an asymmetric-facilitated diffusion system with high Michaelis constants and high maximal velocities; the equivalent permeability in the limit of zero urea concentration is approximately 10(-3) cm/s (J. Gen. Physiol. 81: 221-237, 239-253, 1983). A physiological role for this system is revealed by numerical integration of the appropriate equations that show that rapid urea transport is essential for red cell stability in passing through the renal medulla. The calculation compares two cells. Cell A transports urea with permeability characteristics of normal red cells; cell B has urea permeability similar to lipid bilayers. On entering the hypertonic medulla, both cells shrink, but only B swells on leaving the medulla. The osmotic stress for cell B is greater than for A. Cell B is close to hypertonic hemolysis in the medulla and to hypotonic hemolysis in the cortex. Cell B remains swollen for some time after its exit; the resulting decreased deformability presents a hazard if B reenters the microcirculation. Furthermore, cell B removes a significant fraction of the filtered load of urea and compromises the osmotic gradients in the medulla.

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