Nachweis der Ferredoxin-NADP-Reduktase in der Oberfläche des Chloroplasten-Lamellarsystems mit Hilfe spezifischer Antikörper

Abstract

Antisera against purified ferredoxin-NADP reductase (E.C.1.6.1.1) inhibited photosynthetic NADP-reduction and NADPH2 diaphorase activity of the enzyme. The antisera contained precipitating antibodies against the enzyme. One of the precipitin lines visible after immunoelectrophoretic analysis of the purified reductase was shown to contain diaphorase activity. The antisera against reductase did not agglutinate isolated lamellar systems of chloroplasts directly. Combination of antibodies to reductase, however, with bound reductase in the surface of lamellar systems could be demonstrated and indirect agglutination was observed, when the lamellar systems were incubated with an antiserum against reductase and when subsequently reductase or an antiserum to rabbit-γ-globulin was added. These findings indicate, that at least one antigenic determinant of ferredoxin-NADP reductase is accessible to antibodies at the surface of the lamellar system of chloroplasts. Probably this surface is not plane, but possesses protrusions or deepenings of at least half the length of an antibody molecule (ca. 100 A). In these cavities one or more determinants of bound reductase would be located.