Inactivation constant

Equation 17.13 has been derived without taking account of HRP inactivation by H202, which is described in Equation 17.5. One simple way to remedy this situation is to introduce an inactivation constant into Equation 17.13 ... 

Enzyme-substrate complex Compound III Elorseradish peroxidase Forward rate constant, L/mol-s Reverse rate constant, s 1 Rate constant, s Forward rate constant, L/mol-s Reverse rate constant, s 1 Rate constant, s Forward rate constant, L/mol-s Reverse rate constant, s 1 Rate constant, s Rate constant, s Inactivation constant, mM Constant, mM Constant, mM Pentachlorophenol... 

Summarizing the results of many investigations, monosaccharides and such derivatives as D-mannitol and D-glucitol are rather weak acceptors. Disaccharides, including such acceptor products as isomaltose, are much better acceptors, except for certain molecules, for instance leucrose, which is not an acceptor.29,46,47 The decrease of enzyme activity with time has been described in terms of a first-order reaction. The inactivation parameters have been calculated for the immobilized enzyme. The inactivation constants kd were 0.0135 (1/d) when maltose was the acceptor (stabilizing), and 0.029 (1/d) when fructose was the acceptor.38... 

An enzyme with a higher inactivation constant loses its activity in a shorter time. 

The percentage decreases in the activities of a-amylase incubated at 70, 80, and 85 °C are given in Table 3.1. Calculate the inactivation constants of a-amylase at each temperature. 

Plots of the fractional remaining activity C /C q against incubation time on semi-logarithmic coordinates give straight lines, as shown in Figure 3.3. The values of the inactivation constant k calculated from the slopes of these straight lines are as follows ... 

Temperature"l (K ) empty symbols for amidase activity, (b) Arrhenius plot of inactivation constant obtained from UF-mns. Filled symbols for nitrile hydratase activity empty symbols for amidase activity. 

In the second experiment the reactor feeds were inverted, that is the first feed and the second feed contained 800 and 100 mM of acrylonitrile, respectively. The dynamics of the reactor remained identical (constant flow rate) and the times needed to achieve the first and second steady states in the reactor (fi, t in the scheme) were similar. Interestingly, the inactivation constant evaluated in... 

Detailed structure-activity studies showed that small structural differences in the agents determined whether or not they caused irreversible inactivation. Particularly striking was the conversion of the free carboxylic acid to the methyl ester which gave an agent that had a similar binding affinity [86], but appeared to be completely devoid of ability to irreversibly inactivate the cyclooxygenase activity. The value of the apparent inactivation constants (K ) for the acidic forms of the compounds ranged from zero for ibuprofen and mefenamic acid to 0.0003, 0.04, 0.4 and 1.1 M min for aspirin, indomethacin, meclofenamate and flurbiprofen, respectively [86]. 

Figure 11.7 Inactivation constant during storage of L. paracaei ssp. paracasei as a function of (T-T ) with trehalose as drying matrix. Right-side of the solid line, the matrix is in the rubbery state left-side of the solid line, the matrix is in the glassy state.

With regard to temperature, storage temperature has a large impact on stability. The temperature dependence of the inactivation constant is described by the Arrhenius function ... 

Finally, the different activation energies of the enzyme inactivation, , during nitrile or amide reactions are also reported, and when unavailable, the inactivation constants, kj are given instead. 

Substrate [Substrate] (mM) [Enzyme] ml"l) range (°C) Bioreactor configuration (kjmol 1) Inactivation constant, fe, References... 

Figure 13.2 Inactivation effect, evaluated as inactivation constant, of nitrile concentration on NHase activity. /tj-Values from long-term runs performed in CSMR operated in differential mode and stirred at 250 rpm. The bioreactors were fed with buffered solution...

The production of antibody to T4 bacteriophage has been measured by Howard et al in terms of phage inactivation constant ( 0- Twenty-three days after intravenous immunization with 5 x 10 T4 phage particles, the mean K titre was 5.59 in High responders and 0.033 in Low responders. ... 

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