Highly efficient antibody-catalyzed deuteration of carbonyl compounds.
Antibody 38C2 efficiently catalyzes deuterium-exchange reactions at the alpha position of a variety of ketones and aldehydes, including substrates that have a variety of sensitive functional groups. In addition to the regio- and chemoselectivity of these reactions, the catalytic rates (kcat) and rate-enhancement values (kcat/kun) are among the highest values ever observed with catalytic antibodies. Comparison of the substrate range of the catalytic antibody with highly evolved aldolase enzymes, such as rabbit-muscle aldolase, highlights the much broader practical scope of the antibody, which accepts a wide range of substrates. The hydrogen-exchange reaction was used for calibration and mapping of the antibody active site. Isotope-exchange experiments with cycloheptanone reveal that the formation of the Schiff base species (as concluded from the 16O/18O exchange rate at the carbonyl oxygen) is much faster than the formation of the enamine intermediate (as concluded from the H/D exchange rate), and both steps are faster than the antibody-catalyzed aldol addition reaction.
Shulman
Avidor
A
Department of Chemistry and Institute of Catalysis Science and Technology, Technion-Israel Institute of Technology Technion City, Haifa.
Sitry
Danielle
D
Shulman
Hagit
H
Keinan
Ehud
E
D000447:Aldehydes / Q000737:chemistry*; D000818:Animals; D017151:Antibodies, Catalytic / Q000737:chemistry / Q000378:metabolism*; D002384:Catalysis; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003508:Cycloheptanes / Q000737:chemistry; D003903:Deuterium / Q000737:chemistry*; D005634:Fructose-Bisphosphate Aldolase / Q000737:chemistry / Q000378:metabolism*; D006588:Hexanones / Q000737:chemistry; D007140:Immunoglobulin Fab Fragments / Q000737:chemistry / Q000378:metabolism*; D007659:Ketones / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008742:Methyl n-Butyl Ketone; D008958:Models, Molecular; D015394:Molecular Structure; D009132:Muscles / Q000201:enzymology; D011817:Rabbits; D013379:Substrate Specificity; D013997:Time Factors
D000447:Aldehydes; D017151:Antibodies, Catalytic; D003508:Cycloheptanes; D006588:Hexanones; D007140:Immunoglobulin Fab Fragments; D007659:Ketones; D008742:Methyl n-Butyl Ketone; D003903:Deuterium; C109536:antibody aldolase; D005634:Fructose-Bisphosphate Aldolase; C000363:cycloheptanone