Catalytic antibodies affected

CTAB miceUes " and the subsequent observation that not only lack of hydrogen bonds but also polarity of the solvent are important for catalysis. The catalytic antibody managed to significandy increase the rate acceleration in kc3i conditions, whereas the results on Kjvi were less encouraging and unraveled a common theme that also affects more recent work on the de novo computational design of enzymes. The value of Km for the substrate—antibody pair was found to be 170 pM, a value similar to that measured for bovine serum albumin (125 which likely represents... 

Homogeneous, AM assays pose different requirements. Here, the enzyme should be easily conjugated near the active site without altering its activity. The reaction of hapten- or antigen-labeled enzyme with antibody should affect strongly the enzyme activity, e.g., through steric inhibition of the substrate at the catalytic site. The requirements for optimal ionic conditions and temperature for both enzyme activity and antigen-antibody interaction should be compatible. 

In my own laboratory at Tel-Aviv University we have been testing the effects of different monoclonal antibodies on the activity of carboxypeptidase A [31]. We have found some monoclonal antibodies that inhibit the esterase and peptidase activities of the enzyme, some that inhibit the esterase but not the peptidase activity, others that block the peptidase but not the esterase activity, and yet others that bind to the enzyme but do not markedly affect either of its catalytic activities. Some of the monoclonal antibodies seem to modify the conformation of carboxypeptidase A, thus greatly altering the kinetic parameters of the enzyme. 

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