METABOLIC ACTIVITIES OF SUBCELLULAR PARTICLES FROM AZOTOBACTER VINELANDII

Abstract

When protoplast membranes were taken by sonication, greatest activity was found in the fraction sedimented after 4 hours at 29,000 gravities. Activity was determined respirometrically in a H2 atmosphere using 300 millimolar potassium phosphate at pH 8 with 25 millimolar methylene blue chloride. Fractions (milliliters of hydrogen taken up/hour/mg of N) were: cells[long dash]8,450; protoplasts[long dash]3,250; lysed protoplasts[long dash]1,300 to 1,765; protoplast membranes[long dash]600, and the protoplast soluble fraction[long dash]0. The incorporation N2I5 by protoplast preparations was not as great as with intact cells. Procedures employing lysozymes and chelating agents with various substrates, were discussed. Versene treated cells assimilated N215 comparable with that by protoplasts. Cells with Versene omitted in the treatment mixture (i.e., exposed only to enzyme) were unaffected in N215 uptake.