Metalloantibodies: Mercury(II)-dependent acyl transferases

A new approach for the elicitation of metal-dependent catalytic antibodies for ester hydrolysis is described. A coordinatively unsaturated mercury com plex 1-(Hg), has been utilized as a hapten to elicit antibodies that incorp orate mercury(II) as a Lewis acid cofactor. From a panel of monoclonal anti bodies generated to 1-(Hg), antibody 38G2 was found to hydrolyze the ester 3 in the presence of HgCl2 [K(m)app(3) = 345 muM; K(m)app(Hg2+) = 87 muM; k (cat)app/k(uncat) = 3 x 10(2)]. This is the first example of a biocatalyst that enlists mercuric ion as a cofactor and it is anticipated that this app roach will open new avenues for exploitation of metals thought previously b eyond the scope of protein catalysts. (C) 2001 Elsevier Science Ltd. All ri ghts reserved.