细菌对于蛋白质和氨基酸的代谢试验（Bacterial metabolism tests for proteins and amino acids）.docVIP

细菌对于蛋白质和氨基酸的代谢试验（Bacterial metabolism tests for proteins and amino acids） Bacterial metabolism tests for proteins and amino acids 2009-11-16 10:45 source: medical education network [big and small] [Print] [I want error correction] The principle of bacterial metabolism of proteins and amino acids is that the ability of different bacteria to break down proteins is different. The bacterial decomposition of proteins, usually by extracellular enzyme complex for the decomposition of protein peptide (or amino acid), and then by the infiltration of bacteria in vivo, intracellular enzyme will decompose into the amino acid peptide. Specific test methods: gelatin liquefaction test; the indole test (indol test); the H2S test; the urease test; the phenylalanine deaminase test; the amino acid decarboxylase test. 1. gelatin liquefaction test (1) principle: some bacteria can produce an extracellular enzyme - gelatinase, makes gelatin into amino acids, thus losing the solidification of semi solid, the gelatin medium become flowing liquid. (2) methods: the inoculated bacteria were inoculated on gelatin culture medium and cultured at 22 7d for daily observation. If incubated at 35 DEG C, because the gelatin self liquefaction at this temperature, so before the observation results, first put 4 degrees refrigerator 30min, and then see the results. (3) the result showed that the medium was liquefied and was positive. (4) application: identification of Enterobacteriaceae, such as Serratia marcescens, Proteus mirabilis, Enterobacter cloacae, etc. can be liquefied gelatin, and other bacteria rarely liquefied gelatin. Some anaerobic bacteria, such as Clostridium perfringens and Bacillus fragilis, can also liquefy gelatin. In addition most of Pseudomonas also liquefied gelatin | education network to collect medical education. 2. indole (Dian Jizhi) test (1) principle: some bacteria have tryptophanase, tryptophan indole formation can decompose peptone water (indole), indole reagent (para two wh