ANTIBODY TO LACTATE DEHYDROGENASE .4. ENZYME-INHIBITING AND INHIBITION-INTERFERING COMPONENTS

1. 1. The immunochemical properties of chicken antibodies to rabbit and mouse lactate dehydrogenase (L-lactate: NAD+ oxidoreductase, EC 1.1.1.27), isoenzyme 5, were studied. 2. 2. These antibodies were separated into several distinct fractions by rate zonal ultracentrifugation in a sucrose density gradient and by differential elution from DEAE-cellulose. 3. 3. Immunoglobulins were separated which showed high titers when measured by passive hemagglutination of sheep erythrocytes tanned with rabbit or mouse lactate dehydrogenase but which caused little or no enzyme inhibition. Other immunoglobulins were capable of inhibiting the enzyme but caused little or no passive hemagglutination. 4. 4. Noninhibitory antibodies were shown to interfere strongly with the activity of inhibitory antibody. The removal of noninhibitory antibody yielded anti-lactate dehydrogenase with greatly increased specific activity (45-fold) as measured by enzyme inhibition. © 1969.