AJP - Gastrointestinal and Liver Physiology, Vol 239, Issue 4 266-G271, Copyright © 1980 by American Physiological Society
Subcellular distribution of PRibPP synthetase activity of rat intestinal mucosa
L. C. Yip, A. K. Yeh and M. E. Balis
5-Phosphoribosyl 1-pyrophosphate synthetase (PRibPP synthetase EC 2.7.6.1)
isolated from rat intestinal mucosa was found to be membrane associated.
The subcellular distribution of PRibPP synthetase activity seems to
parallel that of gamma-glutamyl transpeptidase, indicating it to be in the
brush border. The tip cells of rat intestinal mucosa were richer in PRibPP
synthetase than the crypt cells. Chromatography of a Triton-solubilized
particulate fraction unmasked a peak of hypoxanthine
phosphoribosyltransferase activity that was not detectable before. The
activity, too, was concentrated in the brush border. The coexistence of
these two activities in the fraction of the bowl involved in absorption has
led to the suggestin that the synthetase and phosphoribosyl-transferase are
part of a coupled transport system.
