GONUTS has been updated to MW1.31 Most things seem to be working but be sure to report problems.

Have any questions? Please email us at ecoliwiki@gmail.com


Jump to: navigation, search


You don't have sufficient rights on this wiki to edit tables. Perhaps you need to log in. Changes you make in the Table editor will not be saved back to the wiki

See Help for Help on this wiki. See the documentation for how to use the table editor


Loewen, PC and Switala, J (1986) Purification and characterization of catalase HPII from Escherichia coli K12. Biochem. Cell Biol. 64:638-46


Catalase (hydroperoxidase II or HPII) of Escherichia coli K12 has been purified using a protocol that also allows the purification of the second catalase HPI in large amounts. The purified HPII was found to have equal amounts of two subunits with molecular weights of 90,000 and 92,000. Only a single 92,000 subunit was present in the immunoprecipitate created when HPII antiserum was added directly to a crude extract, suggesting that proteolysis was responsible for the smaller subunit. The apparent native molecular weight was determined to be 532,000, suggesting a hexamer structure for the enzyme, an unusual structure for a catalase. HPII was very stable, remaining maximally active over the pH range 4-11 and retaining activity even in a solution of 0.1% sodium dodecyl sulfate and 7 M urea. The heme cofactor associated with HPII was also unusual for a catalase, in resembling heme d (a2) both spectrally and in terms of solubility. On the basis of heme-associated iron, six heme groups were associated with each molecule of enzyme or one per subunit.




Catalase/isolation & purification; Catalase/metabolism; Escherichia coli/enzymology; Isoenzymes/isolation & purification; Isoenzymes/metabolism; Kinetics; Macromolecular Substances; Molecular Weight; Peroxidase; Peroxidases/isolation & purification; Peroxidases/metabolism