How many times a day should I take glutamine?

I just bought L-Glutamine today and I heard its a good supplement to take. I play sports and I lift everyday. I take 100% Whey Protein and 100% Casein Protein. I was wondering how many times I should take L-Glutamine a day. People say you take it when you go to bed, or after workouts, or both. But I don't know when to take it. Also, is it alright if I take it with my Whey and Casein Protein? I'm also 15 and I weigh 162 pounds. I don't know if weight would matter haha!