The technological utility of enzymes can be enhanced greatly by using them in organic solvents rather than their natural aqueous reaction media. Studies over the past 15 years have revealed not only that this change in solvent is feasible, but also that in such seemingly hostile environments enzymes can catalyse reactions impossible in water, become more stable, and exhibit new behaviour such as 'molecular memory'. Of particular importance has been the discovery that enzymatic selectivity, including substrate, stereo-, regio- and chemoselectivity, can be markedly affected, and sometimes even inverted, by the solvent. Enzyme-catalysed reactions in organic solvents, and even in supercritical fluids and the gas phase, have found numerous potential applications, some of which are already commercialized.

Improving enzymes by using them in organic solvents

https://www.creativepegworks.com/peptide_and_protein_pegylation_a_review_of_problems_and_solutions.pdf

Peptide and protein PEGylation: a review of problems and solutions.

4.2. Solid-Supported Electrolytes 2280 4.3. Solid-Supported Mediators 2282 4.4. Supported Substrate-Product Capture 2283 4.5. A Unique Electrolyte/Solvent System 2285 5. Reaction Conditions 2285 5.1. Supercritical Fluids 2285 5.1.1. Electrochemical Properties of scCO2 2285 5.1.2. Electroreductive Carboxylation in scCO2 2286 5.1.3. Electrochemical Polymerization in scCO2 2286 5.2. The Cation-Pool Method 2286 5.2.1. Generation of N-Acyliminium Ion Pools 2286 5.2.2. Generation of Alkoxycarbenium Ion Pools 2287 5.2.3. Generation of Diarylcarbenium Ion Pools 2288 5.2.4. Generation of Other Cation Pools 2289 6. Electrochemical Devices 2289 6.1. Electrode Materials 2289 6.2. Ultrasound and Centrifugal Fields 2290 6.3. Electrochemical Microflow Systems 2290 7. Combinatorial Electrochemical Synthesis 2292 7.1. Parallel Electrolysis Using a Macrosystem 2292 7.2. Parallel Electrolysis Using a Microsystem 2293 7.3. Serial Electrolysis Using a Microsystem 2294 8. Conclusions 2294 9. Acknowledgments 2294 10. References 2294

Modern Strategies in Electroorganic Synthesis

Peroxidase-modified electrodes: Fundamentals and application

Electrochemistry serves as a powerful method for generating reactive intermediates, such as organic cations. In general, there are two ways to use reactive intermediates for chemical reactions: (1) generation in the presence of a reaction partner and (2) generation in the absence of a reaction partner with accumulation in solution as a “pool” followed by reaction with a subsequently added reaction partner. The former approach is more popular because reactive intermediates are usually short-lived transient species, but the latter method is more flexible and versatile. This review focuses on the latter approach and provides a concise overview of the current methods for the generation and accumulation of cationic reactive intermediates as a pool using modern techniques of electrochemistry and their reactions with subsequently added nucleophilic reaction partners.

Electrogenerated Cationic Reactive Intermediates: The Pool Method and Further Advances

Cyclic voltammetry (CV), UV−visible (UV−vis), circular dichroism (CD), and resonance Raman (λex = 406.7, 413.1 nm) spectroscopy have been used to probe the structure and redox function of horse cytochrome c (cyt c) in aqueous mixtures of three water-miscible organic solvents, specifically, acetonitrile (ACN), dimethylformamide (DMF), and dimethyl sulfoxide (DMSO) containing 100−60% water. As the concentration of the organic solvent is increased, significant changes are observed in the spectroscopy of ferricytochrome c (ferricyt c) with the greatest structural changes observed for ferricyt c in mixed solvent media with the lowest dielectric constant (30% ACN in this work). In the UV−visible spectrum, the Soret band blue shifts (1 nm) and the intensity of the 695 nm band decreases. UV CD (185−240 nm) suggest that changes in the protein secondary structure on going from aqueous to nonaqueous media are relatively small and that the protein structure remains largely intact in nonaqueous media. In the visible C...

Cytochrome c Structure and Redox Function in Mixed Solvents Are Determined by the Dielectric Constant

This article summarizes the findings of a survey study of undergraduate research (UR) students presenting their research at the fall 2007 and fall 2008 American Chemical Society (ACS) National Meetings. The purpose of the study is to probe the perceived benefits of conference participation to UR students. Results suggest that participation in professional meetings such as the ACS National Meeting is a vital element of the UR experience and an important factor in the enculturation of student scientists into the greater scientific community. Participation provides student researchers an opportunity to communicate their UR findings to the greater scientific community and strengthens their commitment to the pursuit of a career in chemistry and advanced study. Gender does not appear to influence student views concerning meetings nor student selection of meeting activities. However, ethnicity does appear to influence student views and student selection of meeting activities. Meeting participation appears to provide a forum for African-American students where they feel they can test and affirm their professional self-identity and hone their presentation skills. These findings suggest that participation in technical conferences is an important element in the enculturation of student researchers in the greater scientific community and that meeting participation may be particularly important in the enculturation of African-American student scientists. Student respondents participated in a wide range of activities at the ACS National Meetings, both formal and informal. However, for the most part they elected to participate in the technical activities, specifically, the poster sessions, the exposition, and the undergraduate programming. Comparison of students' stated motivations for attending the ACS National Meeting and their actual selection of meeting activities suggests that students may not be aware of some of the meeting activities nor of the benefits of participating in these activities as they relate to the students' stated meeting goals. Thus, it may be valuable to develop instructional materials and exercises to educate students concerning technical conferences. Finally, UR students attending graduate research universities do not appear to enjoy the same opportunities for participation in professional conferences that their peers attending primarily undergraduate institutions and comprehensive universities do. Since evidence of research experience and productivity are commonly used criteria for offers of graduate school admission and financial aid, this observation merits further study.

Survey Study Investigating the Significance of Conference Participation to Undergraduate Research Students

The use of nonaqueous media To probe biochemically significant enzyme intermediates: The generation and stabilization of horseradish peroxidase compound II in neat benzene solution at room temperature

This contribution reports the first synthesis of conducting polymers (CPs), specifically, polyaniline (PAn) and polypyrrole (PPy), in supercritical carbon dioxide (scCO2). CPs synthesized electrochemically in scCO2 were characterized with cyclic voltammetry (CV), four-point probe conductivity, scanning electron microscopy (SEM), and UV-vis spectroscopy. Preliminary data indicate that CPs synthesized by this method exhibit novel morphology and high conductivity comparable to that synthesized by traditional methods.

Electrochemical synthesis and characterization of conducting polymers in supercritical carbon dioxide.

The effect of the total water content on the persistence and rate of direct heterogeneous electron transfer between the imidazole complex of microperoxidase-11 (im-MP-11) and naked gold, platinum, and glassy carbon (GC) in dimethyl sulfoxide (DMSO) solutions containing 0.1 M tetra-n-butylammonium perchlorate was investigated using cyclic voltammetry. Electron transfer between im-MP-11 and Au, Pt, and GC has been found to be persistent for more than 1 h and at least quasi-reversible [k(s)' = (8.7 ± 0.1) × 10(-4) cm/s (Au), k(s)' = (7.2 ± 1.3) × 10(-4) cm/s (Pt), and k(s)' = (5.7 ± 1.0) × 10(-4) cm/s (GC)] in dimethyl sulfoxide containing an absolute water content between 0.1 and 1.8%. The heterogeneous electron transfer rate constant is independent of the total water content of the DMSO solution when between 0.1 and 1.8% water is present.

Direct electrochemistry for the imidazole complex of microperoxidase-11 in dimethyl sulfoxide solution at naked electrode substrates including glassy carbon, gold, and platinum.

Patricia Ann Mabrouk

Papers

Cytochrome c Structure and Redox Function in Mixed Solvents Are Determined by the Dielectric Constant

Survey Study Investigating the Significance of Conference Participation to Undergraduate Research Students

The use of nonaqueous media To probe biochemically significant enzyme intermediates: The generation and stabilization of horseradish peroxidase compound II in neat benzene solution at room temperature

Electrochemical synthesis and characterization of conducting polymers in supercritical carbon dioxide.

Direct electrochemistry for the imidazole complex of microperoxidase-11 in dimethyl sulfoxide solution at naked electrode substrates including glassy carbon, gold, and platinum.