THANKS to you both! Did´nt have that much time to do the homework - so what a pleasant surprise to find it had been done and then all the additional info from ML.... MERCI BIEN!
Which brings me to a new question..... ;)
NPN - Nitrogen, causing acidic conditions.... is this the last stage (chemical residue) of protein-digestion?
Guess if no one comes up with an answer will really have to go back to doing (some more) homework!
All the best!