scholarly journals Lack of deviation from Michaelis–Menten kinetics for pig heart fumarase

1980 ◽  
Vol 189 (3) ◽  
pp. 653-654 ◽  
Author(s):  
B Andersen
Keyword(s):  
Steady State ◽  
Substrate Concentration ◽  
Substrate Inhibition ◽  
High Substrate Concentration ◽  
High Substrate ◽  
Steady State Kinetics ◽  
Km Value ◽  
Kinetics Of

Studies of steady-state kinetics of fumarase in the usual substrate-concentration range from 0.1 Km to 10 Km and in the high substrate-concentration range from 10 Km to 200 Km are described. The purpose is to investigate reports of substrate inhibition and oscillatory kinetics. In the normal substrate-concentration range, no deviations from hyperbolic kinetics were found, and in the extended concentration range, up to more than 200 times the Km value, no substrate inhibition was demonstrated. A discussion of the discrepancies between the mentioned reports of deviations from the hyperbolic kinetics and the present findings is given.

scholarly journals Studies on alkaline phosphatase. Transientstate and steady-state kinetics of Escherichia coli alkaline phosphatase

1969 ◽  
Vol 111 (2) ◽  
pp. 187-194 ◽  
Author(s):  
H N Fernley ◽  
P. G. Walker
Keyword(s):  
Escherichia Coli ◽  
Alkaline Phosphatase ◽  
Steady State ◽  
Substrate Concentration ◽  
Marked Effect ◽  
Binding Constants ◽  
Transient State ◽  
Steady State Kinetics ◽  
Ph Range ◽  
Kinetics Of

1. The transient-state and steady-state phases of the reaction between Escherichia coli alkaline phosphatase and 4-methylumbelliferyl phosphate were investigated by using a fluorimetric stopped-flow technique. 2. At low substrate concentration (5μm) in the pH range 3·8–6·3 there was an initial rapid liberation of up to 1mole of 4-methylumbelliferone/mole of enzyme. 3. At very low substrate concentration (0·1μm) in the pH range 4·9–5·9 an initial lag in 4-methylumbelliferone production was observed, from which values for k+1 and k−1 could be obtained. 4. The pH profiles for the rates of phosphorylation and dephosphorylation are quite different, and it is postulated that an ionizing group which determines the conformation during the phosphorylation step is not involved in the dephosphorylation step. 5. The binding constants for substrate and Pi are similar throughout the pH range 4–8. The ionization of substrate or Pi appeared to have no marked effect on the binding.

scholarly journals Steady-state kinetic analysis of aldehyde dehydrogenase from human erythrocytes

1992 ◽  
Vol 287 (1) ◽  
pp. 145-150 ◽  
Author(s):  
G T M Henehan ◽  
K F Tipton
Keyword(s):  
Steady State ◽  
Aldehyde Dehydrogenase ◽  
Initial Rate ◽  
Substrate Inhibition ◽  
Human Erythrocytes ◽  
Steady State Kinetics ◽  
Steady State Kinetic ◽  
Sequential Mechanism ◽  
Kinetics Of

The steady-state kinetics of purified cytoplasmic aldehyde dehydrogenase (EC 1.2.1.3) from human erythrocytes have been studied at 37 degrees C. Previous studies of the enzyme from several mammalian sources, which used a lower assay temperature, have been difficult to interpret because of the substrate activation by acetaldehyde which led to complex kinetic behaviour. At 37 degrees C the initial-rate data do not depart significantly from Michaelis-Menten kinetics. Studies of the variation of initial rates as a function of the concentrations of both substrates and studies of the inhibition by NADH were consistent with a sequential mechanism being followed. High-substrate inhibition by acetaldehyde was competitive with respect to NAD+. The enzyme was not inhibited by the product acetate and thus the results of these studies, although consistent with an ordered mechanism in which NAD+ was the first substrate to bind, were inconclusive. That such a mechanism was followed was confirmed by determination of the initial-rate behaviour in the presence of acetaldehyde and glycolaldehyde as alternative substrates. When the reciprocal of the initial rate of NADH formation was plotted against the acetaldehyde concentration at a series of fixed ratios between that substrate and glycolaldehyde, a linear ‘mixed inhibition’ pattern was obtained, confirming the mechanism to be ordered with NAD+ being the leading substrate and with kinetically significant ternary complex-formation.

scholarly journals Strategy for Rapid Recovery of Simultaneous Sulfide and Nitrite Removal under High Substrate Inhibition

2021 ◽  
Author(s):  
Kaiquan Wang ◽  
Mahmood Qaisar ◽  
Bilong Chen ◽  
Siyi Liu ◽  
Yuanyuan Wu ◽  
...  
Keyword(s):  
Substrate Concentration ◽  
Substrate Inhibition ◽  
Process Research ◽  
Sulfide Concentration ◽  
High Substrate Concentration ◽  
Short Term ◽  
High Substrate ◽  
Quick Recovery ◽  
Nitrite Removal ◽  
High Sulfide

Abstract The paper deals with the strategy for a quick recovery of reactor treating sulfide and nitrite simultaneously under inhibition caused by high substrate concentration. For influent sulfide concentration of 360 mg S/L, respective sulfide and nitrite removal percentages dropped to 74.19% and 14.33% due to inhibition caused by high sulfide and nitrite concentrations. It was found that reduction in the influent substrate concentration (300 mg S/L) could not revive the nitrite removal performance in 4 days’ operation, which still showed a declining tendency from 47.16–18.52%. Regulating the influent pH around 6.70 ± 0.10, it only took 4 days to recover the performance for 300 mg S/L. Furthermore, at influent sulfide concentration increased to 360 mg S/L, respective sulfide and nitrite removal percentages were 99.76 ± 0.27% and 100%. The strategy of regulating influent pH could recover the process performance in a short term, which would provide great convenience for subsequent process research.

Steady-state kinetics of valproic acid in epileptic patients

1978 ◽  
Vol 24 (3) ◽  
pp. 324-332 ◽  
Author(s):  
J. Bruni ◽  
B. J. Wilder ◽  
L. J. Willmore ◽  
R. J. Perchalski ◽  
H. J. Villarreal
Keyword(s):  
Valproic Acid ◽  
Steady State ◽  
Steady State Kinetics ◽  
Epileptic Patients ◽  
Kinetics Of

Steady-state kinetics of bezafibrate retard in hyperlipidemic geriatric patients

1988 ◽  
Vol 66 (6) ◽  
pp. 250-256 ◽  
Author(s):  
G. Neugebauer ◽  
D. Platt ◽  
T. Vömel ◽  
W. Lösch
Keyword(s):  
Steady State ◽  
Geriatric Patients ◽  
Steady State Kinetics ◽  
Kinetics Of
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