Re: why is potato a common source of catalase?

The catalase enzyme is present in peroxisomes of most aerobic cells. Potato is 
a good source for several reasons. Potatoes are cheap and readily available 
year round. Potato tissue is also homogeneous and easy to work with. Probably 
part of the widespread use of potato as a source of catalase in student 
experiments is tradition.

Potato does not have the highest catalase activity per gram fesh weight of 
tissue. The University of Colorado at Denver compared the catalase activity in 
about twenty plants and found leek had 3.6 times and parsnips had 6.4 times 
the catalase activity of potato. 

Peroxisomes are important organelles is virtually all eukaryotic cells. They 
have several functions in plants including in photorespiration, germination of 
oily seeds and beta-oxidation of fatty acids. They contain several oxidative 
enzymes and produce hydrogen peroxide. Catalase speeds up the breaking down of 
hydrogen peroxide, which is toxic to cells.

Recent research has found several new roles of plant peroxisomes including in 
auxin biosynthesis, photomorphogenesis, nitric oxide synthesis, sulfite 
oxidase and signal transduction.


References


A Laboratory Experiment Investigating Different Aspects of Catalase Activity 
in an Inquiry - Based Approach 


Catalase Structure


Peroxisomes


PEROXISOMES: ORGANELLES OF DIVERSE FUNCTION


Hydrogen peroxide homeostasis: Activation of plant catalase by calcium 
calmodulin