Upon greening of sorghum leaves (Sorghum vulgare Pers. cv. INRA 450) under white light illumination, phosphoenolpyruvate carboxylase activity increases. 17 times; at the same time, a new isoform of the enzyme appears.
The aim of the present work has been to identify the process responsible for the appearance of this isoform. Greening. of the leaves in the presence of D2O did not lead to a significant increase in the buoyant density of the enzyme. On the other hand, cycloheximide was a powerful inhibitor of the rise in PEP carboxylase activity. In order to clarify these conflicting data a procedure based on the immunoprecipitation of the enzyme and its quantification by gel electrophoresis was developed in order to estimate the amount of enzyme in leaf tissue. The results clearly demonstrate that light triggers an increased synthesis of the enzyme protein during greening of sorghum leaves.
Fluorescent antibody was prepared against a temperate-soil isolate of Beijerinckia obtained from a rhizosphere of rice growing in Camargue (France). The antibody did not cross-react with any of 6 species of Azotobacter, 4 species of Beijerinckia, or 44 unidentified soil bacteria isolated from a spectrum of rhizospheres, but strongly stained the homologous Beijerinckia isolate. The isolate grew well in autoclave Camargue soil, but increased in numbers only slightly in nonsterile soil during 9 days. Preliminary examination of rice plants grown in the laboratory in soil from which the Beijerinckia was originally isolated did not show detectable Beijerinckia in the rhizosphere. The fluorescent antibody was sufficiently sensitive and specific to permit more extensive study of Beijerinckia in relation to nitrogen fixation in the rhizospher of rice.
Summary -The bovine blood plasminogen (Plg) has been purified by affinity chromatography on Lysine-Sepharose. An electrophoresis pattern revealed sorne minor contaminant bands. The possibilities of contamination and activation of Pig have been examined; the Iikely causes of the heterogeneousness are: 1) an in vivo activation just before or during slaughter of the animais; 2) a partial activation during purification; 3) a self-activation or a self-hydrolyse which is a characteristic of proteinases or 4) a contamination of the chromatography column.The milk alkaline proteinase was purified by affinity chromatographies on Lysine-Sepharose and an immunoadsorbant (rabbit anti-bovine plasminogen serum) from whole casein and on enzymeenriched fraction. The purified fractions were partially heterogeneous and presented sorne minor components which are plasmin-chains. This sustains the assumption that self-activation or activation caused by traces of a whey activator in the whole casein occur. Blood and milk purified fractions were compared (electrophoresis, double-immunodiffusion, glycoprotein staining). This paper presents a nover method to purify the milk alkaline proteinase and to confirm the similarities between blood-and milk proteinase. milk alkaline proteinase 1 blood plasminogen or plasmin 1 purification 1 affinity chromategraphy 1 immunological reaction Résumé -Purification de la protéase alcaline du lait et comparaison avec la plasmine ou le plasminogène sanguins bovins purifiés. phy on Lysine-Sepharose will be described. Milk alkaline proteinase was also purified by affinity chromatography on immunoadsorbant using an antiplasminogen serum. Finally the products obtained by these purifications will be compared. Figure 1 depicts the experimental
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