Hydrolysis kinetics kinetic parameters, 304, Table

The individual contributions of the H20, H+, and HO- catalysts to the mechanism of the reaction were further evaluated by means of the kinetics parameters (Table 6.4). At neutral pH, Reactions a and c were both dominated by fcH2<> The second-order rate constants ku+ and kHO- were identical, indicating similar efficiencies of the H+ and HO catalysts. Interestingly, the second-order rate constants for the hydrolysis of Gly-D-Val (6.48) to yield Gly and D-Val (6.49) (Reaction b) could also be calculated (Table 6.4). The similarity to the corresponding rate constants of Reactions a and c suggests that the rate of peptide bond hydrolysis is not particularly sensitive to substitution at or protonation of the flanking amino and carboxy groups [69],... 

Table 11. Kinetic parameters for the hydrolysis of L- and D-ester in a CTAB micelle ...

TABLE 7.1. Kinetic Parameters for the Hydrolysis of Different Peptides by Elastase and Chymotrypsin... 

The kinetics of base hydrolysis of several complexes of the type [Co(NH3)3L3] have been examined in order to see whether the mechanism for these uncharged complexes is the same as that operating for base hydrolysis of the standard cationic complexes (75). A comparison of kinetic parameters - a small selection is given in Table II (76,77) - suggests that all cobalt(III)-nitro-amine complexes, charged and uncharged, undergo base hydrolysis by the SnICB (Dch) mechanism. 

The efficacy of penicillin-type antibiotics is constrained by the ability of bacteria to induce enzymes for their destruction. In relation to this problem, Page and coworkers (Buckwell et al., 1988a,b) have studied the hydrolysis of acylated penicillins [55] and cephalosporins [56] catalysed by a bacterial /3-lactamase (Tables A6.9 and A6.10). It is noteworthy that the two series of substrates show quite different responses to changes in the length of the acyl side chain (C2 to C12). For the penicillins, which are cleaved much more efficiently, there is a broad maximum in the kinetic parameters around C5 to C7, whereas for the cephalosporins there is a linear increase in kc/KM and... 

The polyethylenimines are also effective in the cleavage of nitrophenyl-sulfate esters and nitrophenylphosphate esters. These have not yet been studied as extensively as the acyl esters, but interesting kinetic accelerations are already apparent. Nitrocatechol sulfate, for example, is very stable in aqueous solution at ambient temperature. In fact, even in the presence of 2 M imidazole no hydrolysis can be detected at room temperature. At 95°C in the presence of 2 M imidazole cleavage is barely perceptible. In contrast, a modified polyethylenimine with attached imidazole groups cleaves the sulfate ester at 20°C.34 Some kinetic parameters are compared in Table VI. It is obvious that accelerations of many orders of magnitude are effected by the polymer. 

Rates of hydrolysis of /)-nitrophenyl-P-D-glucopyranoside by P-glucosidase, an irreversible unimolecular reaction, were measured at several concentrations of the substrate. The initial reaction rates were obtained as given in Table 3.2. Determine the kinetic parameters of this enzyme reaction. 

A substrate L-benzoyl arginine /)-nitroanilide hydrochloride was hydrolyzed by trypsin, with inhibitor concentrations of 0, 0.3, and 0.6 mmol 1 T The hydrolysis rates obtained are listed in Table 3.3 [5]. Determine the inhibition mechanism and the kinetic parameters (A", and /Cj) of this enzyme... 

Table 7. Kinetic parameters for hydrolysis of fluorogenic peptide substrate Boc-Leu- ...

Table 1 Kinetic Parameters of Substrate Hydrolysis by Stem Bromelain...

Table 2. Kinetic parameters for trypsin-catalyzed hydrolysis of 8 and 9...

Table 3. Kinetic parameters for tryptic hydrolysis of inverse and normal type substrates ...

Table 4. Kinetic parameters for the trypsin-catalyzed hydrolysis of inverse substrates at pH 8.0,25 °C...

Table VI. Kinetic Parameters of the Hydrolysis of a Dipeptide and Its Related Isodipeptide Catalyzed by Intestinal Aminopeptidase N°...

VI. Table of Information on Hydrolysis Rates and Kinetic Parameters. 91... 

Table 12.5-7. Steady-state kinetic parameters for the hydrolysis of Boc-Xaa-OCp by trypsin according to Thormann et ai.[198].

When the QCM technique was employed for the starch hydrolysis, all kinetic parameters both of the enzyme binding process (kon. koff and JCj) and the hydrolysis process (kcat) could be obtained simultaneously on the same device, as shown in Table 3. In the conventional enzyme reactions in the bulk solution, Michaelis-Menten kinetics have been applied to obtain both the Michaelis constant (Km) and the hydrolysis rate constant (kcat) according to Eq. 16. If koff > kcat, the Km value is thought to be the apparent dissociation constant (K = koff/kon) ... 

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