Effect of Additives on the Selectivity and Reactivity of Enzymes

Abstract

Enzymes have been widely used as efficient, eco-friendly, and biodegradable catalysts in organic chemistry due to their mild reaction conditions and high selectivity and efficiency. In recent years, the catalytic promiscuity of many enzymes in unnatural reactions has been revealed and studied by chemists and biochemists, which has expanded the application potential of enzymes. To enhance the selectivity and activity of enzymes in their natural or promiscuous reactions, many methods have been recommended, such as protein engineering, process engineering, and media engineering. Among them, the additive approach is very attractive because of its simplicity to use and high efficiency. In this paper, we will review the recent developments about the applications of additives to improve the catalytic performances of enzymes in their natural and promiscuous reactions. These additives include water, organic bases, water mimics, cosolvents, crown ethers, salts, surfactants, and some particular molecular additives.

Enhanced activities and thermostability of lipase pretreated with carboxylic and perflurocarboxylic acids in transesterification

“…In the case of a 10 mmol L −1 buffer concentration, the reaction did not proceed at all and the pH of the aqueous solution became 3.5, and in higher buffer concentrations, esterification was successful and the pH of the buffer solution remained at 7. These results indicate pH memory or imprinting, suggesting that the conformation of enzyme was modified by changing the pH of the pretreating aqueous solution . In the following experiments, a 100 mmol L −1 buffer solution was used.…”

“…These results indicate pH memory or imprinting, suggesting that the conformation of enzyme was modified by changing the pH of the pretreating aqueous solution. 1 In the following experiments, a 100 mmol L −1 buffer solution was used. Figure 2 shows the time-courses of transesterification with various lipases (untreated, control and C4F pretreated).…”

“…Many techniques have been developed for enhancing the catalytic activity and thermostability of enzymes in organic media because of the reduction of enzymatic activity in them. Among them, the additive approach is attractive for its simplicity . However, in this method, the product must be separated from the additive.…”

“…Among them, the additive approach is attractive for its simplicity. 1 However, in this method, the product must be separated from the additive. Other methods include the pretreatment of an enzyme prior to using it to enhance activity in an organic medium; its preparation is easy and no additives are required in the reaction system.…”

Biocatalysis and Strategies for Enzyme Improvement

“…Early trial and error experiments with lyophilized (freeze dried) enzyme powders and solvent additives resulted in the development of empirical strategies like addition of water or water-mimicking solvents and addition of salts for stabilizing biocatalysts. The additive approach currently employs the addition of wide variety of lyophilized chemical substances, also known as lyoprotectants, to the media and still appeals to scientists, as it incorporates the simplicity of use and high efficiency [13,14].…”