Three different types of catalases in Klebsiella pneumoniae.

Crude extracts from aerobically grown bacterium Klebsiella pneumoniae contain three different types of catalases, designated KpT, KpCP, and KpA, whose activities in crude extracts are in the ratio 4.1:1:0.3. KpT resembles typical catalases: its molecular weight is 259,000, its activity is independent of pH in the range 5.5-10.5, it is stable at 52 degrees C but loses 80% of its activity when incubated at 60 degrees C for 45 min, and it has hydrophobic properties revealed by binding to phenyl-Sepharose and stability in ethanol-chloroform. KpCP is a catalase-peroxidase with a molecular weight of 278,000, has a sharp pH optimum at 6.3, and is inactivated by treatment at 52 degrees C for 45 min and by ethanol-chloroform. KpA has been reported to be a dimer with molecular weight of 160,000 which contains a chlorin-type heme, has a plateau of maximal activity between pH's 2.8 and 11.8, and is stable to treatment with ethanol-chloroform and to incubation at 70 degrees C. All three enzymes are inhibited by cyanide.