Effect of substrate

S. Garoff, E. B. Sirota, S. K. Sinha, H. B. Stanley. The effects of substrate roughness on ultrathin water films. J Chem Phys 90 7505-7515, 1989. 

The effect of substrate structure on product profile is further illustrated by the reactions of cis- and trons-stilbene oxides 79 and 83 with lithium diethylamide (Scheme 5.17) [32]. Lithiated cis-stilbene oxide 80 rearranges to enolate 81, which gives ketone 82 after protic workup, whereas with lithiated trans-stilbene oxide 84, phenyl group migration results in enolate 85 and hence aldehyde 86 on workup. Triphenylethylene oxide 87 underwent efficient isomerization to ketone 90 [32]. 

The effect of substrate concentration on specific growth rate (/i) in a batch culture is related to the time and p,max the relation is known as the Monod rate equation. The cell density (pcell) increases linearly in the exponential phase. When substrate (S) is depleted, the specific growth rate (/a) decreases. The Monod equation is described in the following equation ... 

Scheme 29 Effect of substrate substituents and catalyst activity on RCM stereochemistry, observed during the total synthesis of ascidiatrienolide (157) [83]...

Scheme 36 RCM-based synthesis of aspicilin (189) effect of substrate substitution on regio-and stereochemistry [93]...

In the discussion of electrophilic aromatic substitution (Chapter 11) equal attention was paid to the effect of substrate structure on reactivity (activation or deactivation) and on orientation. The question of orientation was important because in a typical substitution there are four or five hydrogens that could serve as leaving groups. This type of question is much less important for aromatic nucleophilic substitution, since in most cases there is only one potential leaving group in a molecule. Therefore attention is largely focused on the reactivity of one molecule compared with another and not on the comparison of the reactivity of different positions within the same molecule. 

FIGURE 12.1 Effects of substrate (reactant) concentration on the rate of enzymatic reactions (a) simple Michaelis-Menten kinetics (b) substrate inhibition (c) substrate activation. 

Formation of Polyesters by Pseudomonas oleovorans Effect of Substrates on Formation and Composition of Poly-(R)-3-Hydroxyalkanoates and Poly-(R)-3-Hydroxyalkenoates. Applied Environmental and Microbiology, 54, 2924-2932. 

Figure 8-3. Effect of substrate concentration on the initial velocity of an enzyme-catalyzed reaction.

THE MICHAELIS-MENTEN HILL EQUATIONS MODEL THE EFFECTS OF SUBSTRATE CONCENTRATION... 

Effect of substrate concentration on PG inhibitor Polygalacturonase activity was measured, with or without inhibitor, at different concentrations of the substrate in the reaction mixture to understand the mode of inhibition of polygalacturonase by D. maculata stem inhibitor. The data presented in Fig. 1 indicate that the nature of inhibition is mixed-type. The inhibitor affects both Km as well as Vmax of polygalacturonase. 

We tested the effect of substrate polymerisation level on the PemB specific activity. A mixture of methylated oligogalacturonides was obtained by digestion of 93% methylated pectin by the Aspergillus niger pectin lyase A (20). PemB was more than 100-fold more active on methylat oligogalacturonides than on polymeric pectin. 

Allard A-S, M Remberger, AH Neilson (1985) Bacterial O-methylation of chloroguaiacols effect of substrate concentration, cell density and growth conditions. Appl Environ Microbiol 49 279-288. 

The effect of substrate concentration and the important issue of the existence or otherwise of threshold concentrations below which degradation is not effectively accomplished. 

Extensive studies on the effect of substrate concentration and on the bioavailability of the substrate to the appropriate microorganisms have employed samples of natural lake water supplemented with suitable nutrients. There are few additional details that need to be added since the experimental methods are straightforward and present no particular difficulties. Considerable use has also been made of a comparable methodology to determine the fate of agrochemicals in the terrestrial environment. 

J. P. (2008) Effect of substrate adhesion and hydrophobidty on hydrogel friction. Soft Matter, 4, 1033-1040. 

Table 2. Effect of substrate additions in activity and selectivity for the allylic alkylation reaction (Scheme 1), using [Pd/l]coii as catalyst .

Gsell M, Jakob P, Menzel D. 1998. Effect of substrate strain on adsorption. Science 280 717. 

B. S. Griffits, K. Ritz, N. Ebblewhite, and G. Dobson. Soil microbial community structure Effects of substrate loading rates. Soil Biol. Biochem. 37 145 (1999). 

Figure 3.16 Effects of substrate buildup in a metabolic pathway on the inhibition of an enzyme by competitive (closed circles) and uncompetitive (open circles) inhibitors of equal affinity for the target enzyme.

Table 5.1 Characteristic effects of substrate concentration on the IC50 value for reversible enzyme inhibitors of different modalities...

The inhibition modality for a slow binding inhibitor is easily determined from the effects of substrate concentration on the value of k0bs at any fixed inhibitor concentration (Tian and Tsou, 1982 Copeland, 2000). For a competitive inhibitor the value of fcobs will diminish hyperbolically with increasing substrate concentration according to Equation (6.15) ... 

Examples of the expected effect of substrate concentration on the value of kt)bs for these three inhibition modalities are illustrated in Figure 6.9. 

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