Abstract
A number of application for enzymes in organic solvents have been developed in chemical processing, food related conversions and analyses. The only unsolved problem related to nonaqueous enzymology is the notion that enzymes in organic solvent are mostly far less active than in water. Therefore, studies concerning the mechanisms by which enzymes are inactivated by organic solvents would reveal a clear understanding of the structure-function relationship of this phenomenon. Here we analyzed the effects of a series of alcohols (methanol, ethanol, 1-propanol and 2-propanol) and acetone on the activity of yeast inorganic pyrophosphatase. We observed that solvents inactivated the enzyme in a dose-dependent manner. This inactivation is also dependent on the hydrophobicity of the solvent, where the most hydrophobic solvent is also the most effective one. The I50 for inactivation by n-alcohols are 5.9 +/- 4, 2.7 +/- 1 and 2.5 +/- 1 M for methanol, ethanol and 1-propanol, respectively. Inactivation was less effective at 37 degrees C than at 5 degrees C, when the I50 for inactivation by methanol, ethanol and 1-propanol are 4.5 +/- 2, 2.1 +/- 2 and 1.7 +/- 1 M, respectively. Our proposal is that solvent binds to the enzyme structure promoting the inactivation by stabilizing an unfolded structure, and that this binding is through the hydrophobic regions of either the protein or the solvent.
Highlights
The ability to use enzymes in non-aqueous solvents greatly expands the potential applications of biocatalysts in chemical transformations useful for many industries
Yeast inorganic pyrophosphatase activity was measured in the presence of increasing concentrations of alcohols at 5◦C and at 37◦C
Methanol is the least potent inactivator (I50 = 4.5 ± 0.2 and 5.9 ± 0.4 M for 5◦C and 37◦C, respectively, the cooperativity index, n, were 2.5 ± 0.3 and 1.6 ± 0.2 for 5◦C and 37◦C, respectively), followed by ethanol (I50 = 2.1 ± 0.2 and 2.7 ± 0.1 M for 5◦C and 37◦C, respectively, the cooperativity index, n, were 1.8±0.2 and 1.9 ± 0.2 for 5◦C and 37◦C, respectively), and 1-propanol been the most potent among tested alcohols (I50 = 1.7 ± 0.1 and 2.5 ± 0.1 M for 5◦C and 37◦C, respectively, the cooperativity index, n, were 3.2 ± 0.3 and 2.1 ± 0.2 for 5◦C and 37◦C, respectively). These data suggest that inactivation of inorganic pyrophosphatase by alcohols depends on the hydrophobicity of the solvent
Summary
The ability to use enzymes in non-aqueous solvents greatly expands the potential applications of biocatalysts in chemical transformations useful for many industries. Despite the proposed higher stability in organic solvents, enzymes typically exhibit substantial reduced activity in organic solvents (Lopes and Sola-Penna 2001, Guo and Clark 2001).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
