Subject: How much catalase is in yeast? resubmission

I am doing an investigation to find the rate equation for catalase/H2O2 
reaction. I know this is rate=k[h2O2][catalase] but how do I know the 
concentration of catalase in a certain amount of yeast(or potato)to be able to 
work out a value for k? Are there any standard experiments that have been done 
to estimate the amount of catalase present? The Michaelis-Menten equation also 
has 'concentration of catalase' so how can I use this without knowing how much 
catalase is in the potato and yeast 

Re: How much catalase is in yeast? resubmission