Making up enzyme concentrations

[MariaC]

Hi guys, the yr 11 bio IB class are working on enzymes and Im making up percentage solutions ie 6%, 6g made up to a hundred etc trouble is with some enzymes eg amylase, at higher concentrations the powder clumps at the bottom, I add the water to the required mark, eg 50ml and then use a stirring rod to mix, I then find when I remove the stirring rod the solution has decreased in volume by as much as 5ml I think this is because the powder has absorbed the water but could this be right, I am careful to scrap the stirring rod so Im not removing much liquid so why is so much "disappearing" and what do I do leave it as my original amount was correct or top it up Im confused MariaC

[ellice]

Hi Maria,
Our Yr12 class just did an assessment prac on Enzymes, and I gave them 1% solutions for all enzymes, and they adjusted to what strength they wanted. Didn't have any trouble with dissolving.
Hope this helps.
Ellice.

[MariaC]

Thanks I think Ive figured it out cos it cant just disappear air pockets are forming in the powder as I add the water, when I stir the buddles come up therefore the volume decreases. I just love logic MariaC

[RosalieM]

If you go by weight rather than ml you should be right. 6g then add the water up to 100g. It won't be exactly 100ml because the enzymes weigh more than water although they take up less space.