Proteus enzymes, cell-free

IV. Melezitose Degradation by Cell-free Proteus Enzymes. 287... 

Fig. 4. —Action of cell-free, Proteus enzyme solution upon melezitose, initial concentration 20 mM. Solid circles represent sucrose open circles represent reducing sugars, calculated as glucose.

The ability to oxidize L-amino adds is widespread among bacteria, but the enzymes responsible have not been well characterized. Proteus vulgaris is able to oxidize a large series of L-amino acids, but on storage at 0 C. loses the ability to oxidize 9 out of 20 amino acids tested. The relative rates of oxidation of the other 11 amino adds do not remain constant. An active cell-free preparation was obtained, but it is not known how many amino acid oxidases may exist in these organisms. ... 

Proteus vulgaris has been shown to contain an active L-amino acid oxidase (dehydrogenase) of the anaerobic type (47). The enzyme is sensitive to cyanide and to octyl alcohol (47). While the enzyme has been prepared as a soluble cell-free preparation, the highest activity is obtained with the particulate fraction. Further purification has not been reported, and the nature of the coenzyme is not known. Since this enzyme represents an anaerobic dehydrogenase, no hydrogen peroxide is formed. The fresh bacterial suspension was capable of oxidizing twenty-two different amino... 

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