The proenzyme form of beta-glucuronidase is compartmentalized in large quantities within the endoplasmic reticulum by binding to the esterase, egasyn. Also, the propeptide of the proenzyme form of beta-glucuronidase is likely located at the carboxyl terminus. We have, therefore, tested if this carboxyl-terminal peptide is important in binding to egasyn. A polyclonal antibody to a 30-mer synthet...

We isolated eight known secondary metabolites, including two isocoumarins and six coumarins, from the stems branches of Acer mono Maxim. Their structures were confirmed using nuclear magnetic resonance spectroscopy by comparing data to published reports. The inhibitory effects all compounds (1−8) on Escherichia coli β-glucuronidase evaluated for first time in vitro assays. 3-(3,4-Dihydroxypheny...

The GUS gene of E. coli, encoding b-glucuronidase, has been widely used as a reporter gene in plant transformation. However, b-glucuronidase activity in transgenic wheat leaf or root tissue is rarely observed or reported. To address this question, we investigated three wheat lines transformed with the GUS reporter gene. We found all three lines expressed GUS mRNA as well as b-glucuronidase prot...

A novel approach to reducing organ toxicity of anticancer agents is the application of nontoxic glucuronide prodrugs from which the active drug is released by human beta-glucuronidase, an enzyme present at high levels in many tumors. In view of high interindividual variability in beta-glucuronidase expression, regulation of this enzyme is an essential factor modulating bioactivation of glucuron...

In 1937 Marrian (1) described a reaction where by estriol glucuronide was hydrolyzed during its passage through mouse intestine. This action was ascribed to a $-glucuronidase.' In a series of ex periments, Fishman (2) and others (3) associated the activity of this enzyme more closely with the metabolism of glucuronic acid. The glucuronidase activity of mouse liver was increased following the ad...

Fibroblasts deficient in beta-glucuronidase acquired high levels of this enzyme when they were co-cultured with concanavalin A-stimulated lymphocytes. Acquired enzyme activity, determined using a single-cell cytochemical assay, was directly proportional to the number of lymphocytes added and persisted for several days in fibroblasts maintained at high density. Lymphocytes did not secret signifi...

The interaction between mycophenolate (MPA) and quinolone antibiotics such as ciprofloxacin is considered to reduce the enterohepatic recycling of MPA, which is biotransformed in the intestine from MPA glucuronide (MPAG) conjugate excreted via the biliary system; however, the molecular mechanism underlying this biotransformation of MPA is still unclear. In this study, an in vitro system was est...

The glycoprotein egasyn complexes with and stabilizes precursor beta-glucuronidase in microsomes of several mouse organs. Several observations indicate egasyn is, in addition, an esterase. Liver homogenates of egasyn-positive strains have specific electrophoretically separable esterases which are absent in egasyn-negative mice. These esterases react with anti-egasyn serum. A specific esterase w...

Androgens produced by stimulating mouse testis with gonadotropic hormones cause a rise in renal beta-glucuronidase but not an increase in acid or alkaline phosphatase. All subcellular components increase in beta-glucuronidase activity, with a relatively greater increment in particulate enzyme as compared with that free in the cytoplasm (non-sedimentable). A small percentage of recovered beta-gl...