Lysosomal 3-glucuronidase

In contrast, using enzyme histochemical methods, it was observed that lysosomal (3-glucuronidase was liberated in necrotic tumor areas as functionally active enzyme (75). The cells responsible for the liberation of the enzyme are mainly acute and chronic inflammatory cells, as shown by immunochemistry (74). These observations led to the development of the new concept of prodrug monotherapy (PMT) (74, 75). 

We have recently been able to confirm the findings of Kato and coworkers (1970). Microsomal and lysosomal glucuronidase activities in kidney extracts of animals treated for various time intervals with testosterone propionate were separated electrophoretically at pH 9.5. The staining intensities of the two subcellular components were quantitated densitometrically. After 1 day of treatment, microsomal activity had increased twofold over untreated levels with no significant increase in lysosomal activity. After 2 days, microsomal activity was increased about threefold with a 1 Vi-fold increase in lysosomal activity. (The difference in electrophoretic mobility of the two subcellular components of glucuronidase is discussed in Section IV.)... 

Densitometric analysis of the stained gels shown in Fig. 10 revealed that the anodal zone of liver activity from DBA mice is slightly more intense than the cathodal zone, whereas the intensity of the anodal zone of C3H enzyme is substantially greater than the cathodal zone. This difference suggested the possible identity of the anodal zone with lysosomal glucuronidase activity and the cathodal zone with the microsomal enzyme component, since liver glucuronidase activity of DBA mice is distributed in approximately equal amounts between the lysosomal and microsomal fractions, whereas the activity in livers of C3H animals is predominantly lysosomal (see Section II,A). Examination of enzyme from subcellular fractions substantiated the postulated relationship between the electro-... 

Figure 4. Effect of hyperosmolality on lysosomal enzyme release from rabbit neutrophils. Cells were preincubated 10 min at 37 C in either regular HEPES buffer at 320 mosmol/kg ( ) or in HEPES buffer with 0.3-M sucrose at 680 mosmol/kg ( ), 5 Mg/mL cyto-chalasin B was added, cells were stimulated with FMLP, and p-glucuronidase was released into the medium during a 6-min period measured.

Figure 5. Inhibition of lysosomal enzyme release from neutrophils by increased osmotic strength. Cells were preincubated for 10 min at 37°C in regular buffer containing no additions (o), or containing sodium sulfate ( ), sodium HEPES ( ), or sucrose ( ) to increase the osmotic strength. Cells were treated with cyto-chalasin B (5 arid FMLP (10" M) and p-glucuronidase was...

Figure 5. Continued. Phagocytosis is indicated by the release of the lysosomal enzyme, -glucuronidase. Increased alveolar/capillary permeability is indicated by the increase in protein in the lavage fluid. (Reproduced with permission from ref. 22. Copyright 1988 Academic.)...

Jain, S., Drendel, W., Chen, Z.-W., Mathews, F., Sly, W., and Grubb, J. (1996). Structure of human /3-glucuronidase reveals candidate lysosomal targeting and active-site motifs. 

Careful examination of the yellowish sediment obtained after spinning down the crude mitochondrial fraction showed it was frequently overlaid with loosely packed, fluffy material —the fluffy layer. Experiments from de Duve s and, later, Novikoff s laboratories in the 1950s demonstrated that the lighter, lysosomal fraction was enriched in a number of hydrolases including acid phosphatase, aryl sulphatase, B glucuronidase, RNAase, and a peptidase, cathepsin. All the enzymes had optimal pHs in the acid range (pH 5-pH 6). Density... 

The activity of j8-glucuronidase at the usual pH of the transferase assays (pH 7.4r-8.2) is very low. The enzyme, most likely, has no role in the conjugation process itself (G4). If potentially important, e.g., in work with homogenates or cell extracts containing partially lysed lysosomes, the specific inhibitor saccharo-(l4)-lactone (L9) can be added to the incubation mixtures. 

Marshall, T., Shult, P., and Busse, W.W., Release of lysosomal enzyme p-glucuronidase from isolated human eosinophils, J. Allergy Clin. Immunol, 82, 550, 1988. 

The lysosomal acid phosphatase was cytochemically shown to be present in dense bodies of chondrocytes but not in the nearly matrix vesicles461,462). Subsequent studies have confirmed that the amount of acid phosphatase in isolated vesicles is low and also that the activities of -glucuronidase and cathepsin D in the isolated vesicles were negligible463). The evidence indicates that matrix vesicles are not lysosomal. Isolated vesicles contain comparatively little mitochondrial succinic dehydrogenase, suggesting that the matrix vesicles and mitochondria were not identical458). 

The most clearly documented role lor selenium is as a necessary component of glutathione peroxidase. Selenium is also involved in the functions of additional enzymes, e.g.. type I iodoihvronine deiodinase. leukocyte acid phosphatase, and glucuronidases. A role for selenium in electron transfer has been suggested as has involvement in nonheme iron proteins. Selenium and vitamin b appear to be necessary lor proper functioning of lysosomal membranes. A role for selenium in metabolism of thyroid hormone has been continued. 

Lysosomal storage /1-Glucuronidase Gene replacement Global Multiple injections, anterograde Skorupa et al. (1999) Daly et al. (1999a,b) Sferra et al. (2000)... 

Skorupa, A. F. et al. (1999). Sustained production of beta-glucuronidase from localized sites after AAY vector gene transfer results in widespread distribution of enzyme and reversal of lysosomal storage lesions in a large volume of brain in mucopolysaccharidosis VII mice. Exp. Neurol. 160(1), 17-27. 

Golgi a-l)-mannosidase II lysosomal mannosidase glycoprotein A-linked oligosaccharide processing [toxic, neurotoxic effects mimic hereditary lysosomal storage disease mannosidosis] (3-D-Glucuronidase cx-1-iduronidase Glucosidase... 

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