Charge-relay network

In chymotrypsin and subtilisin, this charge-relay network system, as it is called, is made up of a specific aspartic acid residue, acting as B e, and a specific histidine residue (acting as the amphoteric B—A—H) ... 

Hydrolases possess a common feature for its mechanistic action. Their active site is built around three key amino acid residues, which are histidine (His), serine (Ser), and aspartic acid (Asp) or alternatively glutamic acid (Glu). This site, namely, the catalytic triad, forms a charge-relay network to polarize and activate the nucleophile, allowing the serine hydrolase mechanism to start [19]. This review covers the acylation of alcohols and amines using mainly esters so Figure 9.1 depicts the mechanism for these types of reactions is depicted. 

PCET can also play an important role in interfadal charge transfer processes. Electrochemical PCET have recently been explored, both theoretically and experimentally. Hammes-Schiffer et al. have applied their theoretical framework to model systems where the proton transfer occurs within solvated hydrogen-bonded solute complexes while the electron is transferred between that solute complex and an immersed electrode Costentin et al. have investigated the mechanistic details of PCET in the oxidation of phenols, as model systems of central processes in oxygenic photosynthesis. The same groups have explored the experimental and theoretical aspects of PCET in model systems with proton relay networks. ... 

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