Glucuronidase surface

On the other hand, the Golgi apparatus is implicated in the synthesis of cell-wall membranes. It is possible that the alkaline phosphatase is a catalytically inactive, structural protein of such cell membranes when they are still in the cytoplasm, which may explain many failures to demonstrate its presence in the Golgi apparatus. Upon becoming part of the outer surface, say of the brush border of the intestinal villus, the enzyme may be activated by the alkaline contents of the duodenal lumen. The concept of catalytically inactive membrane enzyme proteins is developed in a recent publication with regard to 8-glucuronidase (FIO). 

To test the concept of attaching an enzyme to the surface. Glucuronidase (GUC) was attached to the functionalized PSi surface. Figure 7 shows an SEM... 

Mansfeld J, Vriend G, Dijkstra BW, Veltman OR, van Den BB, Venema G, Ulbrich-Hofmann R, Eijsink VG (1997) Extreme stabilization of a thermolysin-like protease by an engineered disulfide bond. J Biol Chem 272 11152-11156 Matsuda A, Matsuyama K, Yamamoto K, Ichikawa S, Komatsu K (1987) Cloning and characterization of the genes for two distinct cephalosporin acylases from a Pseudomonas strain. J Bacteriol 169 5815-5820 Matsumura I, Wallingford JB, Surana NK, Vize PD, Ellington AD (1999) Directed evolution of the surface chemistry of the reporter enzyme beta-glucuronidase. Nat Biotechnol 17 696-701... 

There is a recent, detailed account of methods for preparing and characterizing the components of the endoplasmic reticulum (DePierre and Dallner, 1976). Table 2 lists a number of enzymes associated with the endoplasmic reticulum. Several of these enzymes have been localized to the cytoplasmic surface of the reticular membranes, including cytochrome NADH-cytochrome bs-reductase, Mg " -ATPase, 5 -nucleotidase, nucleoside pyrophosphorylase, and GDP-mannosyl transferase. A number of others, including nucleoside diphosphatase, glucose-6-phosphatase, acetanilide-hydrolyzing esterase, and -glucuronidase have been localized to the luminal surface (DePierre and Ems-ter, 1977). Cytochrome P-450 appears to be present at both the cytoplasmic and luminal surfaces. 

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