Catalytic antibody 29G11 (29G11)

Catalytic antibody 29G11 is a murine-derived abzyme (antibody-enzyme) that possesses esterase-like activity, specifically catalyzing the hydrolysis of norleucine phenyl esters with high enantioselectivity for the (S)-enantiomer. It was elicited through immunization with a transition-state analog (TSA), a phosphonate mimic of the tetrahedral intermediate formed during ester hydrolysis. 29G11 is genetically and structurally related to the highly active catalytic antibody 17E8, sharing the same light chain and a similar heavy chain variable region. However, 29G11 is distinguished by a critical mutation at position H99, where a glycine residue replaces the nucleophilic serine found in 17E8, precluding the formation of a covalent acyl-antibody intermediate. Instead, 29G11 achieves rate enhancement through precise transition-state stabilization and potentially general base catalysis. As a model for artificial enzymes, 29G11 provides significant insights into the structural basis of antibody-mediated catalysis and the potential for developing tailored biocatalysts for therapeutic applications such as prodrug activation in cancer therapy.

Other names

Abzyme 29G1129G11 Fab fragment29G11 catalytic antibody

Catalyzes the hydrolysis of esters by stabilizing the tetrahedral transition state. Unlike its homolog 17E8, which uses a Ser-His dyad for nucleophilic catalysis, 29G11 lacks a nucleophilic serine at position H99 (replaced by glycine) and thus does not utilize a covalent acyl-enzyme intermediate, relying instead on non-nucleophilic mechanisms such as general base catalysis and electrostatic stabilization.