Trypsin and Casein? GCSE Biology?

For my GCSE biology we're doing a case study on Trypsin and Casein, and we have to do some research at home. But all the sites I've looked at have confused me, so if you could tell me some of the characteristics, how they work, what does it do and for the enzyme, when does it reach optimum activity linked to temperature? Thanks, any help would be useful :)