Title: The propeptide of beta-glucuronidase. Further evidence of its involvement in compartmentalization of beta-glucuronidase and sequence similarity with portions of the reactive site region of the serpin superfamily Li H, Takeuchi KH, Manly K, Chapman V, Swank RT Ref: Journal of Biological Chemistry, 265:14732, 1990 : PubMed
A significant portion of murine hepatocyte beta-glucuronidase is maintained within the endoplasmic reticulum (ER) by complex formation with the esterase active site of the protein egasyn. The carboxyl-terminal propeptide of the precursor form of glucuronidase appears important in localization of glucuronidase to the ER since a naturally occurring mutation in it is associated with decreased levels of ER glucuronidase. A sequence similarity was noted between the carboxyl-terminal propeptide and portions of the conserved sequences of the reactive site region of members of the serpin (serine proteinase inhibitor) superfamily. Also, previous studies had shown that a synthetic peptide, corresponding to the propeptide region, was a specific and potent inhibitor of the esterase activity of purified egasyn. Taken together, these results suggest that (a) the egasyn-glucuronidase system may use a novel mechanism related to that of serine proteinases and their inhibitors in complex formation and in subsequent localization of glucuronidase within the ER and that (b) a possible function of ER glucuronidase is to modulate the esterase activity of egasyn.
Li H, Takeuchi KH, Manly K, Chapman V, Swank RT (1990) The propeptide of beta-glucuronidase. Further evidence of its involvement in compartmentalization of beta-glucuronidase and sequence similarity with portions of the reactive site region of the serpin superfamily Journal of Biological Chemistry265: 14732-5
Li H, Takeuchi KH, Manly K, Chapman V, Swank RT (1990) Journal of Biological Chemistry265: 14732-5