Specific activity - what does it mean by an enzyme? (Oct/19/2010 )

Dear all,

I have been using the website http://www.brenda-enzymes.org and I have been looking up some information on certain enzymes, I do however have a question about the "SPECIFIC ACTIVITY <�mol/min/mg)". This is one of the parameters the website gives you, but what does this mean?

I havent had a lot of biochemistry and cant find any information about it that I understand.

This is a measurement of how much product is formed by an enzyme in a given amount of time per mg of enzyme . I use specific activity for kinase reactions and what this means is that my kinase is capable of transferring X umol phosphate onto a substrate in a certain amount of time given a certain amount of active kinase. Usually a pure enzyme gives a constant number so this is also a good measurement of an enzyme's purity.

Thank you very much rkay447

the specific activity is especially important if you work with non-pure or crude enzyme preparations