Extracellular proteolytic enzymes of psychrophilic bacteria. I. Purification and some properties of enzymes of an obligately psychrophilic red-pigmented bacterium

Tubular structures of Vibrio psychroerythrus

The marine bacterium Vibrio psychoerythrus, an obligate psychrophile, contains uniformly dense rod-shaped organelles 10-15 nm wide and up to 1.3 mum long. These structures were frequently seen crossing the septum of dividing cells.

Psychrophilic bacteria

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Isolation of an extracellular neutral proteinase from Pseudomonas fragi

A single proteolytic enzyme (EC 3.4.4.-) was isolated from culture supernatants of Pseudomonas fragi with 20% yielded and 60-fold purification by means of stepwise DEAE-Sephadex batch adsorption, ammonium sulfate precipitation, gel filtration and DEAE-cellulose chromatography. The enzyme was Zn-2+ activated and Ca-2+ stabilized, had optimum activity at pH 6.5--8.0 and 40 degrees C. The molecular weight range was 40 000--50 000 as determined by dodecylsulfate gel electrophoresis, gel filtration and Zn assay. This proteinase has properties similar to other extracellular bacterial neutral proteinases.

Differentiation of staphylococcal and micrococcal proteinases by electrophoresis

The electrophoretic separation of the proteinases produced by staphylococci and micrococci was studied in four buffers. The duration of electrophoresis was based on the migration of a marker dye for a predetermined distance. The migration distances of the enzymes and dye were measured, and enzyme-dye values were calculated. A comparison of enzyme-dye values showed that complete separation of eight serologically different proteinases did not occur in any one buffer; however, in most instances, their relative order of migration was the same in all buffers. Certain strains of Staphylococcus epidermidis produced two proteinases that were different serologically as well as electrophoretically. Staphylococcus aureus strains, on the other hand, produced up to four proteinases that were serologically the same. The proteinases of staphylococci and micrococci can be best characterized by both electrophoretic and serological methods.

Removal of nonspecific antiproteinases from serum of rabbits hyperimmunized against Micrococcus and Staphylococcus proteinases

The naturally occurring (nonspecific) proteinase inhibitor which occurs in the alpha globulin fraction of immune rabbit serum was separated from specific staphylococcal and micrococcal antiproteinases by treatment of the antiserum with 2-ethoxy-6-9-diaminacridine. The 2-ethoxy-6-9-diaminacridine-treated serum could then be used to classify these bacterial proteinases by testing directly on casein agar without prior electrophoresis of the serum.