2. Enzymes that attack “N” substrates 1. Urease 2. Gelatinase 3. Nitrate Reductase

3. Urease Urea + water ammonia + carbon dioxide Urea Broth Urea pH Indicator Acidic = Yellow Basic = Pink

4. Gram Reaction Morphology O2Ferment Lactose Urease E. coli (-) Bacilli Facultative (+) (-) Proteus vulgaris (-) Bacilli Facultative (-) (+) Salmonella (-) Bacilli Facultative (-) Shigella (-) Bacilli Facultative (-)

5. Urease Test

6. Gelatinase Gelatin (solid) Gelatin (liquid) Tryptic Soy Gelatin Agar

7. Gelatinase Test

8. Nitrate Reductase Nitrate Nitrite + water Facultative Bacteria Nitrate Broth