Enzyme Stability and Conformation

using vinyl laurate as the acyl donor the enzyme catalyzed the synthesis of 

The conformation and dynamics of secondary structural elements of subtiUsin Carlsberg in 100% DM SO was studied by Fourier-transform infrared (FTIR) spectroscopy and suggested, on one hand, random coil formation at room temperature 

5 depending on the chain length of the alkyl substituent With a racemic mixture of ethyl-2-(4-hexyl phenoxy) propanoate in 65% (v/v) DMSO an T-value of 53 was obtained, whereas in buffer the B-value was 5.4 [25]. A similar effect caused by DMF on a papaya-type plant cystein protease was observed by Quiroga et al. [26], namely a simultaneous increase in hydrolytic activity and parhal unfolding of the enzyme in a mixture of DMF and Tris-HCl buffer pH 8(1 1 v/v). The structural analysis was based on FTIR revealing a decrease in the total content of P-sheet and P-turn secondary structural elements during 4h of incubation. 

At a DMSO concentration of 30% (v/v) Ruiz and De Castro [27] reported that the halo-alkalophilic protease from the archaeon Natrialha magadii showed a residual activity of approximately 80% after 7 days of incubation at 30 °C, 1.5 M NaCl, pH 8 and pH 10, respectively. At suboptimal salt concentrations the presence of DMSO had a stabilizing effect on the enzyme. 

KUbanov [30] and co-workers [31, 32] showed that the tertiary structure of subtilisin Carlsberg was nearly the same in water, acetonitrile, and dioxane and that the differences observed were of the same magnitude as those observed between structures in different aqueous systems. In particular the active site stractures were essentially the same in all three solvents, but also the solvents did not substantially affect the exposed surface area of the enzyme, which was prepared from slightly cross-hnked crystals. 

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