Acceleration of bacterial glutamic decarboxylase and glutaminase by cetylmethylammonium bromide

Abstract

Cell-free extracts containing glutamic decarboxylase and glutaminase were prepared from Clostridium welchii, Proteus morganii and Escherichia coli by grinding the cells with powdered glass, adding buffers to the ground mass and centrifuging. Of the original decarboxylase of the intact cells, about 60% was recovered in extracts from C. welchii, 30-40% from P. morganii and 25-40% from E. coli. The glutaminase activity of extracts was 50-100% of that of the intact cells. The activity both of the decarboxylase and of the glutaminase in the extracts was increased by the addition of cetavlon. The acceleration of the decarboxylase by cetavlon in intact cells and extracts of C. welchii became smaller as the substrate concn. was raised, i. e. the apparent affinitity of the decarboxylase for glutamate seems to be increased by the addition of cetavlon. Bacterial decarboxylases acting on ornithine, tyrosine, arginine, lysine and histidine were not accelerated by the addition of cetavlon, nor was the glutamic decarboxylase of Daucus carota (carrot) or Cucurbita pepo (squash).