Induction of rat alkaline phosphatase isozymes bearing a glycan-phosphatidylinositol anchor modified by in vivo treatment with a benzimidazole derivative linked to ethylbenzene.
Serum alkaline phosphatase (ALP) is detected in soluble-form as a result of translocation from the membrane site by cleavage at the glycosyl-phosphatidylinositol moiety (GPI anchor). It is known that membrane-bound ALP (mALP) can be detected in serum in certain pathological and physiological conditions, and that it can be solubilized in vitro to soluble-ALP (sALP) by phosphatidylinositol-specific phospholipase C (PIPLC), phospholipase D, bile salt, detergent, etc. We observed a marked increase in ALP activity in the serum of rats given a benzimidazole derivative by gavage, and detected it as slow-migrating ALPs (SM-ALPs), which were mALP-like but resistant to PIPLC and n-butanol treatment on disc PAGE. On the other hand, ficin treatment made SM-ALPs shift to the sALP position. The molecular size of the SM-ALPs was smaller than that of sALP on sodium dodecyl sulphide-polyacrylamide slab-gel electrophoresis (SDS-PAGE), and immunoreactivity revealed the intestinal type. SM-ALPs were also detected in the duodenum and jejunum. The main sugar chain structure of SM-ALPs was the biantennary complex-type, which was coincided with intestinal sALP sugar chain. These results suggest that intestinal ALPs induced by the benzimidazole derivative were modified in their C-terminus or GPI anchor region and modification of this region may also participate in translocation into the bloodstream.
Harada
T
T
First Department of Biochemistry, Saitama Medical School, Iruma-gun, Japan. tkalp1lp@saitama-med.ac.jp
Koyama
I
I
Sato
K
K
Komoda
T
T
D000469:Alkaline Phosphatase / Q000097:blood / Q000737:chemistry*; D000818:Animals; D001555:Benzene Derivatives / Q000737:chemistry*; D001562:Benzimidazoles / Q000737:chemistry* / Q000493:pharmacokinetics*; D002846:Chromatography, Affinity; D003208:Concanavalin A / Q000494:pharmacology; D004386:Duodenum / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D017261:Glycosylphosphatidylinositols / Q000737:chemistry*; D006358:Hot Temperature; D007527:Isoenzymes; D007583:Jejunum / Q000378:metabolism; D008297:Male; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D054801:Phosphoinositide Phospholipase C; D011233:Precipitin Tests; D051381:Rats; D017208:Rats, Wistar; D010738:Type C Phospholipases / Q000378:metabolism
D001555:Benzene Derivatives; D001562:Benzimidazoles; D017261:Glycosylphosphatidylinositols; D007527:Isoenzymes; D003208:Concanavalin A; C031000:benzimidazole; D000469:Alkaline Phosphatase; D010738:Type C Phospholipases; D054801:Phosphoinositide Phospholipase C; D043265:Phosphatidylinositol Diacylglycerol-Lyase; C004912:ethylbenzene