Mesophilic enzymes

The DBT sulfone monooxygenase (TdsA) from Paenibacillus sp. strain All-2 has been isolated and characterized by Konishi et al [162], This enzyme was compared with the mesophilic enzyme dszA from R. erythropolis and found to have very little sequence homology however, had similar properties. The molecular mass of the enzyme TdsA was calculated by gel filtration and found to be 120 KDa, whereas with a subunit molecular mass calculated by SDS-PAGE to be 48 KDa. 

Mesophase state, 20 78 Mesophiles, in composting, 25 873 Mesophilic digestion, 3 702 Mesophilic enzymes, 3 669 Mesoporous molecular sieves, 16 847—849 Mesostructured hybrid materials, 13 548-549... 

Professor Sabyasachi Sarkar (bom in 17 May 1947) is an Indian Chemist. He has explored chemistry passionately as a prospector to observe closely the clandestine activities of nature. He has worked and continued working in the diverse branches of chemistry closely related to natural set up and as such his research embraces functional models related to hyperthermophilic to mesophilic metalloproteins enriching bioinorganic chemistry. A Rephca of a Fishy Enzyme and the reduced xanthine oxidase also have been made. Inhibition patterns in the Michaelis complex of low molecular weight hepatic sulfite oxidase model complex have been exhibited. He demonstrated that carbon dioxide molecule does bind... 

Special attention has been paid by sevo groups to cloning xylanase genes from thermophilic microorganisms as a source of thermostable xylanases. Cloning of such genes in mesophilic recepients offers a convenient way to purify xylanases simply by a heat denaturation of the more heat-labile proteins of the host (54). Applications are limited to those enzymes that possess thermostability considerably higher than the majority of the host cell proteins. 

Many examples of the purification of xylanase enzymes to homogeneity can be found in the reviews of Dekker and Richards (85), Woodward (86) and Reilly (87). Other xylanases which have been prepared recently to very high purity using traditional biochemical techniques include xylanases from Sporotrichum dimorphosporum (88) Streptomyces sp. (71) Trichoderma harzianum (5,55) Clostridium acetobuiylicum (30,89) mesophilic fungal strain Y-94 (80) Aspergillus nigcr (90-92) and several thermostable xylanases discussed above. 

When looking for a suitable biocatalyst, one has also to consider the (operational) activity that is required for commercial application and the operational conditions that will be used in the process (e.g. temperature, salt concentration, pH, organic solvents, substrate and product concentration) will have to be addressed as well. If the reaction is optimally performed at for instance high temperatures, thermophilic organisms are more likely to provide the desired enzymes than mesophilic strains (see paragraph 5.4.1). And vice versa, /isychrophiles operate well at lower temperatures and, since they do not require excessive heat treatment to be inactivated, are easily killed following the process. 

Recent structural comparisons between enzymes from mesophiles and thermo-philes have validated numerous protein-stablizing effects, including hydrophobic interactions, packing efficiency, salt bridges, hydrogen bonds, loop stabilization... 

Enzymes from extremophiles, such as thermozymes, have potential either as products themselves, or as catalysts, or they may be used as sources of ideas to modify mesophile-derived enzymes. Most of the thermozymes maintain their thermoresistant properties when expressed in a mesophilic organism such as... 

Some good hints to help answer this question have been obtained by studying thermophilic proteins which are in turn obtained from thermophilic organisms. The optimum growth temperature for thermophilic organisms is between 40° and 65°C (moderate thermophiles) and 70° and 105°C (extreme thermophiles). Their respective enzymes have catalytically indistinguishable reactivity and catalytic sites from those isolated from mesophilic organisms. 

Neoglycosylation of proteins was also applied to the modification of the psychrophilic Atlantic cod trypsin the applicability of psychrophilic enzymes is limited because of their lower thermodynamic stability, despite their higher catalytic rate. It has been shown that the thermodynamic stability could be enhanced appreciably by covalent chemical modification with an oxidized sucrose polymer without affecting the enzymatic activity. The acquired stability of cod trypsin was found to be on par with the mesophilic porcine trypsin.40... 

Arnosti, C., and D. J. Repeta. 1994a. Extracellular enzyme activity in anaerobic bacterial cultures Evidence of pullulanase activity among mesophilic marine bacteria. Applied and Environmental Microbiology 60 840-846. 

Most biochemical studies have focused on enzymes from mesophiles, organisms adapted for life at moderate temperatures ( 20°-40°C)... 

Comparisons of psychrophilic, mesophilic, and thermophilic enzymes suggest that a continuum of adjustments accompany adaptation to different temperatures (Davail et al., 1994 Feller and Gerday, 1997). Relative to mesophiles, the same kinds of weakly stabilizing interactions that are found in greater proportion in thermophilic enzymes appear in fewer numbers in their psychrophilic counterparts. 

Fig. 2. Different thermodynamic strategies for increasing the denaturation temperature of a protein, (a) Free energy curve for a mesophilic enzyme, (b) Thermostabilization by broadening the free energy curve, (c) Thermostabilization by shifting the curve to higher temperatures, (d) Thermostabilization by increasing the free energy of stabilization at all temperatures.

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