Enzyme activity profile

Jessani N, Liu Y, Humphrey M, Cravatt BF. Enzyme activity profiles of the secreted and membrane proteome that depict cancer cell invasiveness. Proc Natl Acad Sci USA 2002 99 10335-10340. 

Jessani N, Flumphrey M, McDonald WH et al (2004) Carcinoma and stromal enzyme activity profiles associated with breast tumor growth in vivo. Proc Natl Acad Sci USA 101 13756-13761... 

It is generally stated that biocatalysis in organic solvents refers to those systems in which the enzymes are suspended (or, sometimes, dissolved) in neat organic solvents in the presence of enough aqueous buffer (less than 5%) to ensure enzymatic activity. However, in the case of hydrolases water is also a substrate and it might be critical to find the water activity (a ) value to which the synthetic reaction (e.g. ester formation) can be optimized. Vahvety et al. [5] found that, in some cases, the activity of Candida rugosa lipase immobihzed on different supports showed the same activity profile versus o but a different absolute rate. With hpase from Burkholderia cepacia (lipase BC), previously known as lipase from Pseudomonas cepacia, and Candida antarctica lipase B (CALB) it was found that the enzyme activity profile versus o and even more the specific activity were dependent on the way the enzyme was freeze dried or immobihzed [6, 7]. A comparison of the transesterification activity of different forms of hpase BC or CALB can be observed in Tables 5.1 and 5.2, respectively. 

The activity of most enzymes depends on pH. The pH-enzyme activity profile of most enzymes delineates a bellshaped curve (Figure 6-3), exhibiting an optimal pH at which activity is maximal. This pH is usually the same as the pH of the fluid in which the enzyme functions. Thus, most enzymes have their highest activity between pH 6 and pH 8 (the pH of human blood is about 7.4). However, pepsin, which must function at the low pH of gastric juice, has maximal activity at about pH 2. 

To demonstrate the utility of a, plots of enzyme activity vs. contain similar shapes and optimal values for a variety of different solvents. - (However, for a given value, the activity for lipophilic solvent is higher than for polar solvent, as discussed above.) Inconsistent trends exist when enzyme activity is plotted against water concentration in solvent rather than In addition, a ,-activity profiles for enzyme preparations that differ only in matrix material have similar shapes and maxima. Exceptions to the commonality of fl ,-enzyme activity profiles include... 

An activity-based probe meeting these requirements could, in principle, enable the comparative measurement and molecular identification of all the active members of a given enzyme class present in one or more proteomes. Importantly, these enzyme activity profiles can be read out in a variety of formats including gels [20,25], microarrays [26], liquid chromatography-mass spectrometry (LC-MS) [27], and capillary electrophoresis [28] (Fig. 7.3-3). 

Fig. 5. a, b Influence of water in the reverse micellar system on enzyme activity, a) Enzyme activity profile in the water pool of chymotrypsin. The substrate is glutatyl-phenyl alanine p-nitro anilide, b) Dependence of the first-order rate constant for peroxidase oxidation of pyrogallol on the content of water solubilized in 0.1 M Aerosol OT plus aqueous buffer (0.02 M phosphate-borate-acetate, pH 7.0) plus octane at 26°C. For comparison, the value of kcat in the same buffer (dashed line) is shown. The initial steady-state rate of formation of purpurogallin was followed spec-trophotometrically (420 nm) (from Ref. [105])... 

Basile F, Ferrer I, Furlong ET, VoorheesKJ. Simultaneous multiple substrate tag detection with ESI-lon trap MS for in vivo bacterial enzyme activity profiling. Anal Chem. 2002 74(16) 4290-3. 

Borowski etal., 1976 Kobel and Sanglier, 1976 Molnar etai, 1964 Udvardy Nagy, E. et al., 1964 Wack et al., 1973), specific colour reaction (Zalai et ah, 1990), fluorescence (Gaberc-Porekar etai, 1981,1983), enzyme activity profiles (Schmauder and Groger, 1983) or antimicrobial effects of clavine alkaloids (Homolka et al., 1985) were worked out. 

Fadnavis, N.W. Babu, R.L., Deshpande, A. 1998. Reactivity of trypsin in reverse micelles pH-effects, on the w versus enzyme activity profiles. Biochimie 80, 1025-1030. 

Godsey, J. H. Matteo, M. R. Shen, D. Tolman, G. Gohlke, J. R. Rapid identification of Enterobacteriaceae with microbial enzyme activity profiles. J. Clin. Microbiol. 1981,13,483-490. 

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