yup those are the exact four I found as well. There are several studies on it and they all seem to indicate that those are the four amino acids for strengthening the mucin lining and it is the mucin lining that is hit very hard in ulcerative colitis. The thing that I don't know is should people take all 4 at the same time? I know that some amino acids compete with each other for absorption but I can't find online which compete with each other.
As far as I remember there were 4 amino acid for improving mucin lining: threonine, serine, proline and cysteine. I tried the threonine 2 g per night, unfortunately didn't do much.
I may give it a shot again with all 4 amino acids.