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HLA-DR2 phenotype and plasma lysozyme, beta-glucuronidase and acid phosphatase levels in pulmonary tuberculosis.

SETTING: Tuberculosis Research Centre, Indian Council of Medical Research, Madras, India. OBJECTIVE: To elucidate the role of HLA-Class II genes/gene products on phagocyte enzymes such as lysozyme, beta-glucuronidase and acid phosphatase in the plasma of pulmonary tuberculosis patients. DESIGN: Serological determination of HLA-DR and -DQ antigens was carried out in 54 active and 84 inactive pulmonary tuberculosis (quiescent) patients and 36 healthy control subjects. The levels of lysozyme, beta-glucuronidase and acid phosphatase were measured in the plasma of tuberculosis patients and control subjects. RESULTS: Increased lysozyme levels were observed in active pulmonary tuberculosis patients. beta-glucuronidase activity was higher in inactive-TB than in active-TB patients and control subjects. HLA-DR2 positive patients showed a lower lysozyme level than -DR2 negative patients. CONCLUSION: Increase in the plasma lysozyme level in active TB reveals the active stage of the disease. Further, increase in the activity of beta-glucuronidase in inactive-TB patients reveals the quiescent stage of the disease. The low level of lysozyme in HLA-DR2 positive patients may also be one of the possible factors involved in susceptibility to tuberculosis.

Acid Phosphatase↗

Construction and characterization of a fusion protein of single-chain anti-CD20 antibody and human beta-glucuronidase for antibody-directed enzyme prodrug therapy.

The CD20 antigen is an attractive target for specific treatment of B-cell lymphoma. Antibody-directed enzyme prodrug therapy (ADEPT) aims at the specific activation of a nontoxic prodrug at the tumor site by an enzyme targeted by a tumor-specific antibody such as anti-CD20. We constructed a fusion protein of the single-chain Fv anti-CD20 mouse monoclonal antibody (MoAb) 1H4 and human beta-glucuronidase for the activation of the nontoxic prodrug N-[4-doxorubicin-N-carbonyl(-oxymethyl) phenyl] O-beta-glucuronyl carbamate to doxorubicin at the tumor site. The cDNAs encoding the light- and heavy-chain variable regions of 1H4 were cloned, joined by a synthetic sequence encoding a 15-amino acid linker and fused to human beta-glucuronidase by a synthetic sequence encoding a 6-amino acid linker. An antibody-enzyme fusion protein-producing cell line was established by transfection of the construct into human embryonic kidney 293/EBNA cells. The yield of active fusion protein was 100 ng/mL transfectoma supernatant. Antibody affinity, antibody specificity, and enzyme activity were fully retained by the fusion protein. Immunoprecipitation and analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) showed that the fusion protein has a relative molecular weight (Mw) of 100 kD under denaturing conditions. Gel filtration analysis indicated that the enzymatically active form of the fusion protein is a tetramer with an Mw of approximately 400 kD. The nontoxic prodrug N-[4-doxorubicin-N-carbonyl(-oxymethyl) phenyl] O-beta-glucuronyl carbamate was hydrolyzed by the fusion protein at a hydrolysis rate similar to that of human beta-glucuronidase. When the fusion protein was specifically bound to Daudi lymphoma cells, the prodrug induced similar antiproliferative effects as doxorubicin. Thus, it is feasible to construct a eukaryotic fusion protein consisting of a single-chain anti-CD20 antibody and human beta-glucuronidase for future use in the activation of anticancer prodrugs in B-cell lymphoma.

Amino Acid Sequence↗

A chromogenic substrate for a beta-xylosidase-coupled assay of alpha-glucuronidase.

4-Nitrophenyl 2-(4-O-methyl-alpha-d-glucopyranuronosyl)-beta-d-xylopyranoside obtained on deesterification of 4-nitrophenyl 2-O-(methyl 4-O-methyl-alpha-d-glucopyranosyluronate)-beta-d-xylopyranoside (Hirsch et al., Carbohydr. Res. 310, 145-149, 1998) was found to be an excellent substrate for the measurement of hemicellulolytic alpha-glucuronidase activity. A new precise alpha-glucuronidase assay was developed by coupling the alpha-glucuronidase-catalyzed formation of 4-nitrophenyl beta-d-xylopyranoside with its efficient hydrolysis by beta-xylosidase. A recombinant strain of Saccharomyces cerevisiae, harboring and expressing the beta-xylosidase gene xlnD of Aspergillus niger under control of the alcohol dehydrogenase II promoter on a multicopy plasmid, was used as a source of beta-xylosidase. The activity values of beta-xylosidase in the assay required to achieve a steady-state rate of 4-nitrophenol formation shortly after starting the alpha-glucuronidase reaction were obtained both experimentally and by calculation using the kinetics of coupled enzyme reactions.

Aspergillus niger↗

Purification and characterization of an extracellular alpha-D-glucuronidase from Phlebia radiata.

Alpha-D-glucuronidase was isolated from the culture filtrate of Phlebia radiata grown on wheat bran and purified to homogeneity by chromatographic methods. The final enzymic preparation was purified 65-fold with an activity yield of 58%; it showed a high level of specific activity (over 23,000 nkat/mg protein). The molecular and hydrolytic properties of the purified enzyme were studied. The secreted alpha-glucuronidase had a molecular weight of 110 kDa, as established by gel permeation chromatography (GP HPLC), had a determined pI just below 4.4, and was stable at pH 5.5 for prolonged times. The carbohydrate content in protein molecules was found to be 15%. The activity of alpha-D-glucuronidase peaked at pH 3,8 and 60 degrees C with aldouronic acids preparation as the substrate. The Michaelis-Menten constant (K(m)), the maximum reaction velocity (V(max)), and the activation energy (E(a)) were 0.18 mM, 0.13 microM/min and 5.91 kJ/mol, respectively. The alpha-glucuronidase was active mainly on small substituted xylooligomers. When this enzyme was used with endoxylanase for the degradation of oat xylan, synergistic effects were observed.

Biodegradation, Environmental↗

aguA, the gene encoding an extracellular alpha-glucuronidase from Aspergillus tubingensis, is specifically induced on xylose and not on glucuronic acid.

An extracellular alpha-glucuronidase was purified and characterized from a commercial Aspergillus preparation and from culture filtrate of Aspergillus tubingensis. The enzyme has a molecular mass of 107 kDa as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and 112 kDa as determined by mass spectrometry, has a determined pI just below 5.2, and is stable at pH 6.0 for prolonged times. The pH optimum for the enzyme is between 4.5 and 6.0, and the temperature optimum is 70 degrees C. The alpha-glucuronidase is active mainly on small substituted xylo-oligomers but is also able to release a small amount of 4-O-methylglucuronic acid from birchwood xylan. The enzyme acts synergistically with endoxylanases and beta-xylosidase in the hydrolysis of xylan. The enzyme is N glycosylated and contains 14 putative N-glycosylation sites. The gene encoding this alpha-glucuronidase (aguA) was cloned from A. tubingensis. It consists of an open reading frame of 2,523 bp and contains no introns. The gene codes for a protein of 841 amino acids, containing a eukaryotic signal sequence of 20 amino acids. The mature protein has a predicted molecular mass of 91,790 Da and a calculated pI of 5.13. Multiple copies of the gene were introduced in A. tubingensis, and expression was studied in a highly overproducing transformant. The aguA gene was expressed on xylose, xylobiose, and xylan, similarly to genes encoding endoxylanases, suggesting a coordinate regulation of expression of xylanases and alpha-glucuronidase. Glucuronic acid did not induce the expression of aguA and also did not modulate the expression on xylose. Addition of glucose prevented expression of aguA on xylan but only reduced the expression on xylose.

Amino Acid Sequence↗

[Expression and purification of thermostable alpha-glucuronidase from Thermotoga maritima].

The xylanolytic enzymes found in Thermotoga maritima showed extremely high thermostability and considerable potential in industrial application. Yet expression level of the genes encoding these enzymes was very low. The alpha-glucuronidase gene aguA from T. maritima ATCC 43589 was cloned and expressed in several E. coli strains with different vector. The alpha-glucuronidase was overexpressed in E. coli BL21-CodonPlus(DE3)-RIL with plasmid pET-28a(+), and made up about 20% of the total proteins present in the intracellular soluble fraction. The results proved the assumption that rare codons for arginine (AGA/AGG) and isoleucine (AUA) affect the expression of aguA gene from hyperthermophilic bacterium T. maritima in E. coli. Purification procedure included two steps, heat treatment and immobilized metal affinity chromatography, and over 13.5mg of pure enzyme was obrained from 1L of induced culture. The purified enzyme showed a single band on SDS polyacrylamide gel electrophoresis with a purification of 5.1 fold, and a yield of 55.1%. The optimum activity of recombinant alpha-glucuronidase was found at pH 6.0 and 85 degrees C, the enzyme retained 70% of its activity after 1 h of incubation at 85 degrees C. The induction conditions for expression of recombinant strain BL21-CodonPlus(DE3)-RIL/pET-28a-aguA were studied on induction time and duration by IPTG. The results showed that the activity of thermostable alpha-glucuronidase reach the maximum in 5-hour after inducted at the exponential phase (OD600 of 0.7 - 0.8).

Escherichia coli↗

Urinary beta-glucuronidase activity as an initial screening test for urinary tract malignancy in high risk patients. Comparison with conventional urine cytologic evaluation.

BACKGROUND: Routine urine cytology is not particularly useful as a screening test for urinary tract malignancy in the general population, due to its low detection rate. Bladder, ureteral, and pelvic lavage and flow cytometry increased the test sensitivity but could be applied only to a limited number of patients. A simple, sensitive screening test is needed. METHODS: Two hundred eighty-two urine samples from 146 patients from the Urology Tumor Clinic patients during their initial visits were subject to cytologic evaluation and measurement of the activity of endogenous beta-glucuronidase, followed by confirmation procedures, including cystoscopy with biopsy, ultrasonography, radiography and/or computed tomography. RESULTS: Among 146 patients, 32 had confirmed transitional cell carcinoma and 14 renal cell carcinoma. The urinary beta-glucuronidase activity was higher in patients with cancer than in those without cancer in the Urology Service and in 80 normal healthy control subjects. The accuracy of the urine enzyme diagnostic system measured by the receiver-operating characteristic (ROC) plot was 98% or higher based on the number of patients. The upper threshold value determined by ROC analysis was 1.7 nmol/min/mumol creatinine. At this threshold value, the sensitivities of the enzyme assay for transitional cell carcinoma, renal cell carcinoma, and all cancers were, respectively, 94%, 98%, and 95%. These values were much higher than the corresponding sensitivities of urine cytology: 41%, 0%, and 22%. CONCLUSION: Urinary beta-glucuronidase is a much more sensitive test to screen for urinary tract malignancy than routine urine cytology in high risk patients, provided that a positive test is followed by diagnostic procedures for confirmation.

Adult↗

Simultaneous, two-color fluorescence detection of total protein profiles and beta-glucuronidase activity in polyacrylamide gel.

A dichromatic method for measuring the specific activity of beta-glucuronidase from complex cell homogenates or partially purified protein fractions is presented. Dual fluorescence is achieved by using the green emitting fluorogenic substrate ELF 97 beta-D-glucuronide to detect beta-glucuronidase activity, followed by the red emitting SYPRO Ruby protein gel stain or SYPRO Ruby IEF gel stain to detect the remaining proteins in the electrophoretic profile. Both ELF 97 alcohol, the highly fluorescent hydrolytic product generated from the enzyme substrate, and the SYPRO Ruby total protein stains are maximally excited by ultraviolet illumination. ELF 97 alcohol emits maximally at 525 nm while the SYPRO Ruby dyes emit maximally at 610 nm. Since ELF 97 beta-glucuronide is a precipitating substrate, it allows precise localization of beta-glucuronidase activity with minimal band diffusion. The staining method is simple and direct, without the requirement for ancillary coupling reactions. Dichromatic protein detection is demonstrated after sodium dodecyl sulfate(SDS)-polyacrylamide gel electrophoresis, carrier ampholyte-mediated isoelectric focusing or two-dimensional gel electrophoresis.

Electrophoresis↗

GUS fusions: beta-glucuronidase as a sensitive and versatile gene fusion marker in higher plants.

We have used the Escherichia coli beta-glucuronidase gene (GUS) as a gene fusion marker for analysis of gene expression in transformed plants. Higher plants tested lack intrinsic beta-glucuronidase activity, thus enhancing the sensitivity with which measurements can be made. We have constructed gene fusions using the cauliflower mosaic virus (CaMV) 35S promoter or the promoter from a gene encoding the small subunit of ribulose bisphosphate carboxylase (rbcS) to direct the expression of beta-glucuronidase in transformed plants. Expression of GUS can be measured accurately using fluorometric assays of very small amounts of transformed plant tissue. Plants expressing GUS are normal, healthy and fertile. GUS is very stable, and tissue extracts continue to show high levels of GUS activity after prolonged storage. Histochemical analysis has been used to demonstrate the localization of gene activity in cells and tissues of transformed plants.

Cloning, Molecular↗

Prenatal diagnosis of a heterozygote for mucopolysaccharidosis type VII (beta-glucuronidase deficiency).

We had the opportunity of investigating a case (BK) of a severe form of mucopolysaccharidosis with nearly total deficiency of beta-glucuronidase in serum, leucocytes and fibroblasts. We here report results obtained by prenatal diagnosis of a clinically normal child (BK's sister), and point out the difficulty in interpreting a heterozygous level of beta-glucuronidase activity in cultured amniotic cells. Four successive passages of amniotic cells were tested for beta-glucuronidase and alpha-mannosidase activity in at-risk and control cells. In different passages, enzyme activity was between 8 and 49 per cent of controls but 2 to 18 times higher than fibroblasts from the affected brother (BK). The highest activity was observed in the first passage and the lowest in the third. The electrophoretic separation of GAGS from at-risk amniotic fluid showed a normal pattern. We discuss the correlation between enzyme levels in different passages of cultured cells and that found in leucocytes and fibroblasts from the propositus and parents. From a practical point of view, we conclude that the first passage gives the most reliable results for prenatal diagnosis.

Adult↗

The signal for retention of the egasyn-glucuronidase complex within the endoplasmic reticulum.

Egasyn is localized within the lumen of the endoplasmic reticulum (ER) where it complexes with and thus causes sequestration of a considerable portion of beta-glucuronidase. Egasyn has an HTEL sequence at its carboxyl terminus rather than the KDEL sequence that serves as a retention signal for many ER lumenal proteins. To determine whether the HTEL sequence acts as an ER retention signal and/or functions in complex formation, HTEL-deleted egasyn was expressed in mammalian cell lines. The majority of HTEL-deleted egasyn was secreted, while wild type egasyn was retained in the ER. Furthermore, the egasyn HTEL sequence, when added to the carboxyl termini of two secretory proteins, mouse esterase, Es-N, and rat alpha 1-acid glycoprotein (AGP), caused retention of both proteins within the ER, demonstrating that the HTEL sequence is both necessary and sufficient for retention of egasyn and, by extension, the egasyn-glucuronidase complex within the ER. Other carboxyl terminal tetrapeptides including HIEL and HVEL, naturally occurring in other ER lumenal proteins, were also sufficient for ER retention of AGP, while HTEHT and HTEHK were inefficient in ER retention. The HTEL sequence, in contrast, is not required for egasyn-glucuronidase complex formation. Further, the complex is apparently unstable outside the ER since it was not visible in the medium of cells transfected with egasyn lacking the HTEL sequence despite abundant secretion of this egasyn. These results show that it is possible to localize proteins within the lumen of the ER if they form complexes with ER lumenal proteins containing an intrinsic ER retention sequence.

Amino Acid Sequence↗

Human sperm beta-glucuronidase is poorly extractable by Triton X-100.

A part of sperm glycosidase activities was detected as detergent-insoluble after sequential extractions with Triton X-100. Sixty per cent of total beta-glucuronidase activity was found in the detergent-insoluble fraction. This portion of beta-glucuronidase was resistant to extractions in the presence of 1 M KCl, chaotropic agents, colchicine or cytochalasine B, being only partially solubilized by 3 M KCl or DNAse I treatment. Results demonstrate that beta-glucuronidase is tightly associated to the Triton X-100 resistant fraction.

Actins↗

Characterization and immunolocalization of beta-D-glucuronidase in mouse testicular germ cells and spermatozoa.

Spermatozoa released from the seminiferous tubules are terminally differentiated cells with no known synthetic activity. Their components are synthesized in the spermatogenic cells during spermatogenesis. In this study, we report the characterization and immunolocalization of beta-glucuronidase in mouse testicular germ cells and spermatozoa. The enzyme is an exoglycohydrolase with dual localization, being present in lysosomes and endoplasmic reticulum of several mouse and rat tissues. The purified germ cell preparations (spermatocytes, round spermatids, and condensed/elongated spermatids) when assayed for beta-glucuronidase activity showed that the spermatocytes contained five times more enzyme activity per cell than the spermatids. Polyacrylamide gel electrophoresis, carried out under native and denaturing conditions, demonstrated that the germ cells express only the lysosomal form of the enzyme (pI 5.5-6.0) with a subunit molecular mass of 74 kDa. Immunocytochemical studies revealed a positive reaction in the Golgi membranes, Golgi-associated vesicles, and lysosomes of late spermatocytes (pachytene spermatocytes) and a stage-specific localization during spermiogenesis. The forming or formed acrosome of the elongated spermatids (stages 9-16) and epididymal spermatozoa was highly immunopositive. Comparison of immunoprecipitation curves and kinetic properties of the enzyme present in spermatocytes and spermatozoa revealed no major differences. Taken together, our results demonstrate that beta-glucuronidase activities present in the lysosomes of spermatocytes and the sperm acrosome are kinetically and immunologically similar.

Animals↗

Significantly increased expression of beta-glucuronidase in the central nervous system of mucopolysaccharidosis type VII mice from the latency-associated transcript promoter in a nonpathogenic herpes simplex virus type 1 vector.

Herpes simplex virus (HSV) has the ability to establish life-long latent infections in postmitotic neurons and to remain transcriptionally active, continuously expressing latency-associated transcripts (LAT) while producing minimal disease. These properties have made HSV an excellent candidate for neuronal gene transfer. Previously, we have shown that in mucopolysaccharidosis type VII mice (MPS VII, beta-glucuronidase deficiency) the LAT promoter is capable of expressing beta-glucuronidase (GUSB) in the trigeminal ganglion and the brainstem after latency is established. However, the number of neurons expressing GUSB is much lower than the number expressing 2-kb LAT following a wild-type virus infection. In this study, we have evaluated the effect of the position of the coding sequence relative to the LAT promoter on beta-glucuronidase gene expression in the central nervous system (CNS). Non-neurovirulent (ICP-34.5-deleted HSV-1) vectors were used, allowing direct intracranial injection. Significantly more GUSB activity was detected in brains of MPS VII mice inoculated with a recombinant virus (HSV-LAT-GUSB-JS) in which the GUSB cDNA was inserted near the LAT promoter, compared to viruses where it was inserted farther downstream in either the LAT exon 1 or overlapping exon 1 and the 2-kb LAT intron. This vector produced more than 100 times the number of positive cells than the other constructs. During acute infection, the distribution of viral replication differed from the distribution of GUSB enzyme expression. Viral antigen was predominately present in cells around the site of injection in the caudate putamen and in ependymal cells lining the ventricles. In contrast, GUSB expression was present mainly in cells of the thalamus and hypothalamus, which did not exhibit viral antigen, suggesting that GUSB enzyme activity was expressed from latently but not acutely infected neuronal cells. This vector design should be useful for high-level expression of various genes in the CNS.

Animals↗

Differential diagnostic value of acid phosphatase and beta-glucuronidase in acute leukaemia.

Differential diagnostic importance of acid phosphatase and beta-glucuronidase reactions was studied in bone marrow smears of 52 patients with acute leukaemias. Both reactions showed either diffuse or simultaneously diffuse and granular positivity in the medullary blast cells of 34 patients suffering from ANLL. A strong diffuse positivity of acid phosphatase suggested the possibility of AMOL. Beta-glucuronidase and acid phosphatase reactions were exclusively granular in every positive case of ALL. Increased acid phosphatase activity was found in T-ALL while beta-glucuronidase showed increased activity also in (non-T, non-B)-ALL on several occasions.

Acid Phosphatase↗

Progressive induction of beta-glucuronidase in individual kidney epithelial cells.

The magnitude and kinetics of beta-glucuronidase induction in mouse kidney are determined by a cis-acting regulatory gene, Gus-r, that is closely linked to the enzyme structural gene. The accumulation of beta-glucuronidase mRNA during induction is much slower than the turnover time of the mRNA, suggesting progressive acquisition of mRNA synthesizing capacity during induction. Counts of the numbers of induced cells present at various times of induction in strains carrying three different alleles of Gus-r show that all potentially responsive cells respond immediately. The level of induction is progressive in individual cells and does not involve continued recruitment of new cells into the induced population. It appears that during induction each chromosome becomes progressively more active in directing the synthesis of beta-glucuronidase.

Animals↗

Glycosaminoglycan accumulation with partial deficiency of beta-glucuronidase in the C3H strain of mice.

Young (60--80 days) mice of the low beta-glucuronidase strain, C3H/HeJ, showed no differences in hepatic levels of glycosaminoglycans (GAGs) when compared to the randombred, "normal" Swiss-Webster mice of the same age. However, by 12 months of age hepatic GAG is nearly twice as high in C3H/HeJ mice as in Swiss-Webster mice. Studies of beta-glucuronidase, beta-galactosidase, and N-acetyl-beta-glucosaminidase in four tissues of the two types of mice at the two ages revealed that glucuronidase was the only enzyme with lower activity in the C3H/HeJ strain.

Aging↗

Expression of beta-glucuronidase haplotypes in prototype and congenic mouse strains.

A gene complex consists of a structural gene with its associated regulatory information; together they behave as the functional and evolutionary unit of mammalian chromosomes. The use of congenic lines, in which alternate forms, or haplotypes, of a gene complex are transferred into a common genetic background by repeated backcrossing, provides a means of comparing the regulatory properties of different haplotypes of a gene complex without the complications introduced by extraneous genetic differences. We have now carried out such a study of the A, B, and H haplotypes of the beta-glucuronidase gene complex, [Gus], in mice. These haplotypes were derived from strains A/J, C57BL/6J, and C3H/HeJ and were compared against the C57BL/6J genetic background. Enzyme structure was compared in terms of charge (isoelectric point), stability (rate of thermal denaturation), substrate affinity (for 4 MU glucuronide), and antigenicity (reactivity with a standard antibody). Compared to the B form, the enzyme coded by the A haplotype has a lower isoelectric point, and that coded by the H haplotype is less stable. The decreased stability is the result of a lower activation energy for the thermal denaturation reaction. These differences were maintained in the congenic strains. All three enzyme forms showed identical substrate affinities. Antigenicity per enzyme unit was also identical for all three, indicating that none lacks an antigenic site possessed by the others and that they all possess the same catalytic activity per molecule. The expression of alleles of the Gus-t temporal locus within the gene complex was not affected by transfer into the C57BL/6 genetic background. The same developmental switches in enzyme activity were seen in each case. Transfer into the C57Bl/6 background also did not affect expression of the Gus-r regulator determining androgen inducibility of beta-glucuronidase synthesis in kidney epithelial cells. However, enzyme accumulation in induced cells was altered when the haplotypes were transferred into the C57BL/6 genetic background. Since the rate of synthesis was not affected, it suggests that the genetic differences between strains that are not linked to the [Gus] complex affect the rate of enzyme loss by degradation or secretion. Beta-Glucuronidase in liver is present in both lysosomes and endoplasmic reticulum (microsomes). The relative amount of enzyme at each site depended on both the indentity of the structural allele and the function of unlinked genetic modifiers. Within the C57BL/6 background the percentage of total enzyme present in the microsome fraction was the order A greater than B greater than H. For the H form of the enzyme the percentage was appreciably greater in the C3H genetic background compared to C57BL/6. As expected, then, the [Gus] complex contains all of the genetic determinants of enzyme structure detected by thermal stability and isoelectric point measurements...

Animals↗