The Enzymic Activity of the Outer Shell of Lactobacillus arabinosus

Abstract

SUMMARYPreparations of the outer shell of Lactobacillus arabinosus were made by crushing the bacteria in a Hughes press and removing the cytoplasm by washing and centrifugation. Such preparations had none of the enzymes associated with flavin-mediated oxidation; they had consistently adenosine triphosphatase (ATPase) activity. The kinetics and other properties of this enzyme were studied. The evidence suggested that the enzyme was bound to the cytoplasmic membrane, the bulk of which appeared to be within the cell wall. The preparation was thus similar to that from obligate facultative aerobes and which, in contrast to the preparations from lactobacilli, contained enzymes associated with oxygen utilization mediated by the cytochrome hydrogen transport system. The bound ATPase had an optimum at pH 6.0 and was not markedly inhibited by ouabain or oligomycin: it was stimulated by 2,&dinitrophenol. It was thus different from ATPase associated with ion transport but similar to that from mitochondria1 membranes. There was no nucleotide pyrophosphorylase activity in the preparation but other nucleotide triphosphates and diphosphates and some inorganic phosphates were hydrolysed but at slower rates than was ATP.

The Action of Lysozyme on Bacterial Electron Transport Systems

“…embedded in 'cell wall', or accessible to NADH, only from its outer aspect. The report by Cole & Hughes (1965) that ATPase activity in Lactobacillus arabinosus was released on prolonged sonic treatment, to a much higher degree than that obtained merely by breaking of the organisms in the Hughes press, presents an analogy with our findings. Ability to react with cytochrome c after lysozyme treatment is also of some interest in view of the almost uniformly negative results obtained on numerous occasions when bacteria or bacterial extracts have been examined for ' cytochrome oxidase' (see Smith, 1954Smith, , 1961 Lysozyme ultimately inactivated the NADH, oxidase system in disintegrated or lysed organisms though the loss of activity was much less rapid than with succinate oxidase.…”

The Autolysis of Clostridium sporogenes

“…A similar but less marked increase had previously been seen with preparations of certain lactobacilli (Cole & Hughes, 1965). Experiments with crushed C .…”

Adenosine Phosphate Hydrolases in Cell Fractions of Vitreoscilla

“…The hydrolysis of both ATP and ADP is stimulated by MgH, as are all bacterial adenosine triphosphatases (1,3,5,7,12,20,22). As reported in the Results, our enzymes were not directly stimulated by Ca++, K+, or Nat.…”