Changing enzymatic conformation in organic media with pH buffer lyophilized powder

Nie, Guangjun; Cai, Wenlong; Yao, Zhengyu; Zhu, Zhubin; Zhu, Xiangxiang; Zheng, Z. P.; Yue, Wenjin

doi:10.1016/j.catcom.2015.02.025

Cited by 2 publications

(1 citation statement)

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“…In fact, as water acts as a molecular lubricant [94][95][96], enzyme structure is very rigid in those media with an almost null water activity (this thermodynamic parameter is better than water amount to define the water-dependence of enzyme behavior [97,98]), so that in pure organic solvents crystalline enzymes do retain their native structures [99]. Another fascinating peculiarity associated with the use of enzymes in organic solvent is the concept of "pH memory" [100][101][102][103][104][105]; that is, the enzymatic conformation in an aqueous solution at a certain pH value can be "solidified" by lyophilisation, as protein ionogenic residues would retain the previous ionization state, which would be retained in the organic solvent. This fact, initially observed with water, promoted the development of ligand bio-imprinting technology, initially described by Mosbach et al [106,107], through the lyophilization of the enzyme and a substrate analogue (forming a complex similar to the enzyme-substrate complex) in the aqueous solution and a further removing of the substrate analogue.…”

Section: Use Of Enzyme In Organic Solvents With Low Water Activitymentioning

confidence: 99%

Enzyme-Coated Micro-Crystals: An Almost Forgotten but Very Simple and Elegant Immobilization Strategy

et al. 2020

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The immobilization of enzymes using protein coated micro-crystals (PCMCs) was reported for the first time in 2001 by Kreiner and coworkers. The strategy is very simple. First, an enzyme solution must be prepared in a concentrated solution of one compound (salt, sugar, amino acid) very soluble in water and poorly soluble in a water-soluble solvent. Then, the enzyme solution is added dropwise to the water soluble solvent under rapid stirring. The components accompanying the enzyme are called the crystal growing agents, the solvent being the dehydrating agent. This strategy permits the rapid dehydration of the enzyme solution drops, resulting in a crystallization of the crystal formation agent, and the enzyme is deposited on this crystal surface. The reaction medium where these biocatalysts can be used is marked by the solubility of the PCMC components, and usually these biocatalysts may be employed in water soluble organic solvents with a maximum of 20% water. The evolution of these PCMC was to chemically crosslink them and further improve their stabilities. Moreover, the PCMC strategy has been used to coimmobilize enzymes or enzymes and cofactors. The immobilization may permit the use of buffers as crystal growth agents, enabling control of the reaction pH in the enzyme environments. Usually, the PCMC biocatalysts are very stable and more active than other biocatalysts of the same enzyme. However, this simple (at least at laboratory scale) immobilization strategy is underutilized even when the publications using it systematically presented a better performance of them in organic solvents than that of many other immobilized biocatalysts. In fact, many possibilities and studies using this technique are lacking. This review tried to outline the possibilities of this useful immobilization strategy.

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