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Query: EC:3.2.1.31 (
beta-glucuronidase
)
7,680
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The activities of prolyl 4-hydroxylase (PH) and galactosylhydroxylysyl glucosyltransferase (GGT), both enzymes of collagen biosynthesis, were measured in the gastrocnemius, soleus, and tibialis anterior muscles of rats after bilateral cast-immobilization of the muscles in lengthened and shortened positions for one and three weeks. The activities of muscular proteolytic and hydrolytic enzymes cathepsin D (CD),
beta-glucuronidase
(beta-GU),
alkaline protease
(AP), and the rate of acid autolysis (AA) were also studied. The biochemical results were compared to the morphologic changes by light microscopy. Compared to the results for a control group, there was a decrease of 37% and 53% in the specific PH activity of shortened gastrocnemius and soleus, respectively, after three weeks of immobilization. The corresponding decrease in GGT of the shortened gastrocnemius was 47%. At the same time, PH and GGT in the lengthened plantarflexors were at the control level. The proteolytic activities of the shortened plantarflexors were generally higher (CD by approximately 30%, beta-GU of gastrocnemius by 81%, AP of soleus by 63%, AA of gastrocnemius by 34%, and AA of soleus by 56%) than those of the lengthened ones. Light microscopy of the shortened muscles showed numerous atrophic fibers, but no pronounced inflammatory response in the disused muscle tissue. The results suggest that increased proteolysis and wasting of muscle tissue during cast-immobilization is associated with adaptive responses in the metabolism of the muscular collagen network.
...
PMID:Collagen synthesis and proteolytic activities in rat skeletal muscles: effect of cast-immobilization in the lengthened and shortened positions. 305 21
The activities of cathepsin D (CD),
beta-glucuronidase
(beta-GU),
alkaline protease
(AKP), and the rate of acid autolysis (AA) were measured in gastrocnemius, soleus, and tibialis anterior muscles of the rat after bilateral cast immobilization in the middle position for one and three weeks. The effects of daily indirect electric stimulation on the proteolytic activities of immobilized muscles were also studied. In gastrocnemius and tibialis anterior, electric stimulation partially prevented the loss of muscle weight after immobilization for one week. Activities of CD and beta-GU were highest in the soleus, but the activities did not change therein after immobilization or electric stimulation. In gastrocnemius, the activities of CD and AKP and the AA rate increased significantly after immobilization. Electric stimulation during immobilization seemed to prevent the increase of CD and AKP activities significantly after one (CD) and three (AKP) weeks immobilization. In tibialis anterior, the activities of CD and AKP and the AA rate increased significantly in the stimulated muscles after immobilization for three weeks. Both in the gastrocnemius and tibialis anterior the beta-GU activity increased significantly in the stimulated muscles. The results suggest that during the disuse atrophy process and electric stimulation of immobilized muscles, rat hind-limb muscles differ in acid and alkaline proteolytic responses.
...
PMID:Acid and alkaline proteolytic activities of cast-immobilized rat hind-limb muscles after electric stimulation. 330 95
The activities of four lysosomal and two nonlysosomal hydrolases were studied in skeletal muscle biopsy samples from patients with neuromuscular diseases and from controls. beta-Glucosaminidase activity was increased in polymyositis. beta-Glucuronidase and
alkaline protease
activities were elevated in muscular dystrophy in adults, whereas cathepsin D activity was increased in amyotrophic lateral sclerosis. There were significant correlations between the activities of lysosomal and nonlysosomal hydrolases. The activity of
beta-glucuronidase
, beta-glucosaminidase,
alkaline protease
, and dipeptidyl aminopeptidase IV showed a positive correlation with the severity of muscular atrophy. The activities of these hydrolases and the activity of dipeptidyl aminopeptidase I correlated positively with the activities of muscular galactosylhydroxylysyl glucosyltransferase and with the serum concentration of type III procollagen aminoterminal propeptide. The results suggest that in neuromuscular diseases the lysosomal and nonlysosomal pathways for muscle degradation are affected concomitantly with collagen biosynthesis.
...
PMID:Lysosomal and nonlysosomal hydrolases of skeletal muscle in neuromuscular diseases. 635 16
This study aimed at comparing the effects of running and swimming training protocols and the termination of training on the activities of two proteases with alkaline pH-optima (
alkaline protease
and myofibrillar protease) in the tibialis anterior, soleus, and gastrocnemius muscles of male rats. The training on treadmill decreased the activities of alkaline and myofibrillar proteases by approx. 10-20% in the muscles studied. The activities of both proteases were unchanged in swimming-trained rats. Two weeks after the termination of running training the activity of
alkaline protease
was increased in gastrocnemius muscle but not in the other muscles. Swimming training increased the activity of citrate synthase in all muscles studied but training by running only in the soleus muscle. The running protocol increased the activity of
beta-glucuronidase
in the tibialis anterior muscle and decreased the activity in the gastrocnemius muscle. The swimming program did not affect
beta-glucuronidase
activities. These results show diverse effects of running and swimming training on alkaline proteolytic activities as well as on mitochondrial and lysosomal marker enzymes.
...
PMID:Effects of endurance training on alkaline protease activities in rat skeletal muscles. 636 35
Alkaline and myofibrillar protease activities of rectus femoris, soleus, and tibialis anterior muscles and the pooled sample of gastrocnemius and plantaris muscles were analyzed in male NMRI-mice during a running-training program of 3, 10, or 20 daily 1-h sessions. The activity of citrate synthase increased during the endurance training, reflecting the increased oxidative capacity of skeletal muscles. The activities of alkaline and myofibrillar proteases continually decreased in the course of the training program in all muscles studied. Instead, the activity of
beta-glucuronidase
(a marker of lysosomal hydrolases) increased in all muscles. The highest activities were observed at the beginning of the training program. Present results, together with our earlier observations, show that the type of training, running as opposed to swimming, modulates the training responses in
alkaline protease
activities. Further, diverse adaptations in the activities of alkaline proteases and a lysosomal hydrolase suggest difference in the function of different proteolytic systems.
...
PMID:Endurance training decreases the alkaline proteolytic activity in mouse skeletal muscles. 637 21
Leupeptin, a nontoxic thiol protease inhibitor, has been proposed to have therapeutic use in hereditary muscular dystrophies. The purpose of this study was to characterize the in vivo changes in proteolytic activity of skeletal muscles induced by the repeated administration of leupeptin. Further, whether the modulation of proteolytic capacity by leupeptin affects the repair process of muscle injuries caused by heavy exercise was studied. Leupeptin was administered in mice intraperitoneally at a dose level of 15.5 mg/kg twice a day for 9 days. Leupeptin, known to be an inhibitor of cathepsin B both in vitro and after a single injection in vivo, paradoxically induced an increase of cathepsin B activity in mouse skeletal muscles after repeated administration. In addition, leupeptin administration for 9 days increased the activities of cathepsins C and D, as well as the rate of acid autolysis. The activity of
beta-glucuronidase
also increased, while those of arylsulfatase, ribonuclease, and
alkaline protease
were unaffected. No histopathologic changes were observed. At the low dosage used, leupeptin had no effect on the repair process of skeletal muscle after exercise injuries, although several proteolytic processes occur during the regeneration. It is suggested that the increase of acid protease activities in skeletal muscles is an adaptive response to the administration of the proteolytic inhibitor leupeptin and that leupeptin can be administered without prevention or delay of regenerative processes after the onset of myopathic changes.
...
PMID:Effects of the protease inhibitor leupeptin on proteolytic activities and regeneration of mouse skeletal muscles after exercise injuries. 638 26
Madin Darby bovine kidney (MDBK) cells were used as a source to identify novel bovine chemotactic factors for granulocytes and monocytes. A major bovine granulocyte chemotactic protein (GCP-2) has previously been isolated. A novel bovine monocyte chemotactic protein (bo
MCP
) was produced on MDBK cells stimulated with phorbol ester. The 14-kDa protein was purified to homogeneity by adsorption to controlled pore glass, heparin affinity chromatography, cation-exchange FPLC, and RP-HPLC. The amino acid sequence of the NH2-terminally blocked protein was determined by Edman degradation using proteolytic fragments. The primary structure of the bo
MCP
, characterized by four conserved cysteines, allowed classification of the protein within the C-C chemokine family. Bo
MCP
-1B was most related to known human and bovine MCPs. Compared to bovine MCP-1 and MCP-2, the protein consists of 84% and 53% identical amino acids, respectively. Since this bo
MCP
was also most homologous to human and animal MCP-1, it was designated bo
MCP
-1B. The minimal effective dose of bo
MCP
-1B for monocyte chemotactic activity was 0.2 mM. The maximal migration index, reached at 2 nM, was comparable to that of natural human MCP-1. Furthermore, bo
MCP
-1B was found to be capable of stimulating
beta-glucuronidase
release from monocytes. In contrast, bo
MCP
-1B was not chemotactic for neutrophilic and eosinophilic granulocytes. By its biological and biochemical characteristics, bo
MCP
-1B has to be considered as an authentic additional MCP-1 chemokine. The existence of a possible human counterpart for this novel
MCP
-1B still needs to be elucidated.
...
PMID:Purification, sequence analysis, and biological characterization of a second bovine monocyte chemotactic protein-1 (Bo MCP-1B). 794 49
Conjugation of multiple ubiquitins serves as a committed step in the degradation of a variety of intracellular eukaryotic proteins by the 26S
proteasome
. Conjugates are formed via a three-enzyme cascade; the initial step requires ubiquitin-activating enzyme (E1), which couples ubiquitin activation to ATP hydrolysis. Previously, we showed that many higher plants contain multiple E1 proteins and described several E1 genes from wheat. To facilitate understanding of the roles of the different plant E1s, we characterized the E1 gene and protein family from Arabidopsis thaliana. Arabidopsis E1s are encoded by two genes (AtUBA1 and AtUBA2) that synthesize approximately 123-kDa proteins with 81% amino acid sequence identity to each other and 44-75% sequence identity with confirmed E1s from other organisms. Like other E1 proteins, AtUBA1 and 2 contain a cysteine residue in the putative active site for forming the ubiquitin thiol-ester intermediate. Enzymatic analysis of the corresponding proteins expressed in Escherichia coli demonstrated that both proteins activate ubiquitin in an ATP-dependent reaction and transfer the activated ubiquitin to a variety of Arabidopsis E2s with near equal specificity. Expression studies by quantitative RT-PCR and histochemistry with transgenic plants containing AtUBA promoter-
beta-glucuronidase
-coding region fusions showed that the AtUBA1 and 2 genes are co-expressed in most, if not all, Arabidopsis tissues and cells. Collectively, the data indicate that E1 proteins, and presumably the rest of the ubiquitin pathway, are present throughout Arabidopsis. They also show that the AtUBA1 and 2 genes are not differentially expressed nor do they encode E1s with dramatically distinct enzymatic properties.
...
PMID:The ubiquitin-activating enzyme (E1) gene family in Arabidopsis thaliana. 907 89
A major goal of plant biotechnology is the production of genetically engineered crops that express natural or foreign proteins at high levels. To enhance protein accumulation in transgenic plants, we developed a set of vectors that express proteins and peptides as C-terminal translational fusions with ubiquitin (UBQ). Studies of several proteins in tobacco (Nicotiana tabacum) showed that: (a) proteins can be readily expressed in plants as UBQ fusions; (b) by the action of endogenous UBQ-specific proteases (Ubps), these fusions are rapidly and precisely processed in vivo to release the fused protein moieties in free forms; (c) the synthesis of a protein as a UBQ fusion can significantly augment its accumulation; (d) proper processing and localization of a protein targeted to either the apoplast or the chloroplast is not affected by the N-terminal UBQ sequence; and (e) single amino acid substitutions surrounding the cleavage site can inhibit in vivo processing of the fusion by Ubps. Noncleavable UBQ fusions of
beta-glucuronidase
became extensively modified, with additional UBQs in planta. Because multiubiquitinated proteins are the preferred substrates of the 26S
proteasome
, noncleavable fusions may be useful for decreasing protein half-life. Based on their ability to augment protein accumulation and the sequence specificity of Ubps, UBQ fusions offer a versatile way to express plant proteins.
...
PMID:Use of ubiquitin fusions to augment protein expression in transgenic plants. 995 68
Arabidopsis plants possess a family of nine AtAtg8 gene homologues of the yeast autophagy-associated Apg8/Aut7 gene. To gain insight into how these genes function in plants, first, the expression patterns of five AtAtg8 homologues were analysed in young Arabidopsis plants grown under favourable growth conditions or following exposure to prolonged darkness or sugar starvation. Promoters, plus the entire coding regions (exons and introns) of the AtAtg8 genes, were fused to the
beta-glucuronidase
reporter gene and transformed into Arabidopsis plants. In all plants, grown under favourable growth conditions,
beta-glucuronidase
staining was much more significant in roots than in shoots. Different genes showed distinct spatial and temporal expression patterns in roots. In some transgenic plants,
beta-glucuronidase
staining in leaves was induced by prolonged darkness or sugar starvation. Next, Arabidopsis plants were transformed with chimeric gene-encoding Atg8f protein fused to N-terminal green fluorescent protein and C-terminal haemagglutinin epitope tags. Analysis of these plants showed that, under favourable growth conditions, the Atg8f protein is efficiently processed and is localized to autophagosome-resembling structures, both in the cytosol and in the central vacuole, in a similar manner to its processing and localization under starvation stresses. Moreover, treatment with a cocktail of
proteasome
inhibitors did not prevent the turnover of this protein, implying that its turnover takes place in the vacuoles, as occurs in yeasts. The results suggest that, in plants, the cellular processes involving the Atg8 genes function efficiently in young, non-senescing tissues, both under favourable growth conditions and under starvation stresses.
...
PMID:The autophagy-associated Atg8 gene family operates both under favourable growth conditions and under starvation stresses in Arabidopsis plants. 1615 55
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