Cool,

marine biology, that's a field I've always been interested in.
One point though, (too many molecular biology classes), I understand the whole concept of denaturation via heat, pH, etc etc. But I don't understand why it matters whether a protein
that is going to be digested is biologically active or not.
I can see how the digestive enzyme itself has to be in it's optimal environment but why must the protein to be digested also be in its original conformation?
One possible argument I can foresee would be that fish have digestive enzymes that are more particular, only able to break down proteins in certain conformations. I have no clue whether that's true or not seeing that I know little about fish physiology. But in humans, we break down and absorb about 98% of all the protein in our diet, with our broad spectrum enzymes and what not, randomly cleaving here n there.
Anyways, could you explain how come the conformation of the protein that is going to be digested matters?
Thanks
PS. Good luck with your paper, seems like a really interesting topic.