Structure of Catalase:
Catalase is an enzyme that catalyzes the decomposition of hydrogen peroxide
to water and oxygen:
2 H2O2 -----> 2 H2O + O2
Hydrogen peroxide is produced within the cell as a byproduct of several different
biochemical reactions. Unfortunately, hydrogen peroxide is a strong oxidant
and is highly toxic. In order to avoid its build-up within the cell, catalase
rapidly decomposes it to water and oxygen. In fact catalase is one of the fastest
and most efficient enzymes known. Several different types of catalases are known.
The structure of beef liver catalase is shown below (right click for display
options)
Some key features of the structure are:
-
The enzyme is made up of two identical subunits (homodimer)
-
The active site contains an iron porphyrin group (iron heme)
-
The iron center is bound by a tyrosine group
-
Hydrogen peroxide is believed to bind the Fe center
-
NADP (nicotinamide adenine dinucleotide phosphate, shown in purple) acts
as a co-factor.
The structure was obtained from Protein
Structural Databank which is operated by the Research Collaboratory for
Structural Bioinformatics (RCSB) under a contract to the U.S. National Science
Foundation
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Created 02/22/00
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