![]() ![]() Moreover, different forms of cations result in different reaction rates allowing us to tune the reaction time scales from seconds to hours. Apart from the reaction acceleration for positively-charged micelles of cetrimonium chloride (CTAC), benzethonium chloride (BTC), and cetylpyridinium chloride (CPC), we prove that when anionic, (sodium dodecyl sulfate - SDS) or neutral (Brij L23) surfactants are used, the reaction rates are similar to the one in water or buffer. In contrast to common micellar catalysis, the reactions occur exclusively on the surface of the charged micelles 7. By introducing positively charged micelles to the reaction system, an up to 5 million-fold rate enhancement is observed compared to the same reaction in water. 1, which can be followed conveniently by the increase in fluorescence intensity. As a first model reaction, we investigate the reaction between coenzyme A (CoA) and bromo-N-methylmaleimide substituted coenzyme A (CoA-M), as shown in Fig. In this work, we systematically study how the reaction kinetics of two independent experimental systems (i.e., covalent and non-covalent product formation) were influenced by the nature of the charges and the form in which charges were introduced, i.e., salt ions, charged monomers (or their oligomers), charged micelles, and charged polymers. Inspired by this finding, we aim to answer whether the rate enhancement by ’counter-charged’ species could be a general phenomenon and explain the theoretical basis of such electrostatic catalysis. Recently, we discovered a significant acceleration of the chemical reaction between negatively charged reactants when positively charged polymers were added, which we attributed to the sliding of the reactants along molecular tracks (so-called diffusive binding) 6. There has been a vast interest in synthetic enzymes or enzyme-mimics such as nanozymes, but capturing the properties of the active site of enzymes with respect to charge stabilization has been challenging and typically highly selective for specific reactions 3, 4, 5. Warshel has shown that electrostatic effects and the stabilization of charges provide a key catalytic contribution 2. In biological systems, these reactions are usually accelerated by enzymes acting as catalysts. ![]() Thus, such reactions in pure water can take days or even weeks 1. For the effective product formation between like-charged molecules, additional energy is required to overcome Coulomb repulsions. Whether a given transformation occurs is controlled by the nature of the charge positive or negative, its quantity, surrounding atoms, and distribution among molecules. The occurrence of any chemical reaction requires its reactants to meet in the correct spatiotemporal manner and with sufficient energy. A theoretical analysis shows that the acceleration is correlated to the catalysts’ surface charge density in both experimental systems and enables predicting and controlling reaction rates of like-charged compounds with counter-charged species. We generalize the observed phenomenon by analogously speeding up a non-covalent complex formation-DNA hybridization. Rate enhancements are not limited to micelles, as evidenced by significant catalytic effects (10 4–10 5-fold) of other highly charged species such as oligomers and polymers. That is ~10 4 faster kinetics than in 0.5 M NaCl, although the salt is ~10 6 more concentrated. The reaction between negatively charged Coenzyme A molecules accelerates ~5 million-fold using cationic micelles. Here, we demonstrate that by screening these interactions and, in consequence, increasing the local concentration of reactants, we boost the reactions by many orders of magnitude. The reaction kinetics between like-charged compounds in water is extremely slow due to Coulomb repulsions. ![]()
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