A peculiar alkaline phosphatase isoenzyme appeared in patients with ulcerative colitis

Abstract

We have already reported a peculiar alkaline phoaphatase (ALP) isoenzyme (ALP₆) appeared in the sera of ulcerative colitis patients. Enzymological and immunological characteristics of this ALP₆ were studied.
The following results were obtained:
1) ALP₆ was detected in the sera from 4 out of 20 cases (20%) with ulcerative colitis.
2) In active stage of the disease, ALP₆ appeared along with decrease of hepatic ALP. ALP₆ disappeared in remission.
3) The characteristics of ALP₆ was similar to hepatic ALP with respect to the inhibition by L-phenylalanine, imidazole and L-homoarginine. As to the heat-stability at 56°C and inhibition by urea, ALP₆ resemble more closely to bone ALP.
4) Active band of ALP₆ on polyacrylamide-gel disc electrophoresis disappeared after treatment with anti-human hepatic ALP antibody, but was not affected with anti-human intestinal or placental ALP antibody. Therefore, ALP₆, found in ulcerative colitis, seems to be a modified enzyme of hepatic ALP.