Where are multisite blog admins saved?

Hi,

i have one multisite blog named test with admins called testadmin and testadmin2.

I want to remove testadmin2 from this multisite blog using a plugin.

My idea:
Take a look into the database an remove the user with an simple sql-query.

But: i cant find any table where multisite admins are stored..

Do u know where they are stored in the database?

Thanks a lot!