Evolution of Binding Affinity and Catalytic Efficiency

103- and 105-fold over background. Although their activity is typically many orders of magnitude below that of comparable enzymes, they generally exhibit programmable and enzyme-like regio- and stereoselectivity. 

Acyl transfer has been the most thoroughly investigated process with respect to antibody catalysis. Attention paid to such systems reflects the broad utility of hydrolytic enzymes, on the one hand, and the availability of excellent transition state analogs, on the other. 

Phosphonates and phosphonamidates, which mimic the tetrahedral geometry and anionic character of the transition state for hydrolysis, have proven especially reliable as haptens. Antibodies generated against such compounds readily promote the cleavage of esters and, in a few cases, amides. High levels of stereospecificity are attainable even at chiral centers remote from the reaction site [11]. 

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