Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.24.56 (insulin-degrading enzyme)
 737 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have recently described the purification and characterization of an insulin-degrading enzyme (IDE) from Drosophila melanogaster that can cleave porcine insulin, is highly conserved through evolution and is developmentally regulated. We now report that the IDE is, in fact, an insulin EGF-binding protein (dp100) that we had isolated previously from Drosophila using an antihuman EGF receptor antiserum. This conclusion is based upon the following evidence. (a) dp100, identified by its ability to cross-link to labeled insulin, EGF, and transforming growth factor-alpha (TGF-alpha), and to be immunoprecipitated by anti-EGF receptor antisera, copurifies with the IDE activity. Thus, the purified IDE can be affinity labeled with either 125I-insulin, 125I-EGF, or 125I-TGF-alpha, and this labeling is specifically inhibited with unlabeled insulin, EGF, and the insulin B chain. (b) The antiserum to the human EGF receptor, which recognizes dp100, is able to specifically immunoprecipitate the insulin-degrading activity. (c) The purified IDE preparation contains a single protein of 110 kD which is recognized by both the anti-EGF receptor antiserum and anti-Drosophila IDE antiserum. (d) Polyclonal antiserum to the purified IDE, which specifically recognized only the 110-kD band in Drosophila Kc cells, immunoprecipitates dp100 cross-linked to 125I-TGF-alpha and dp100 cross-linked to 125I-insulin from the purified IDE preparation. (e) EGF, which competes with insulin for binding to dp100, also inhibits the degradation of insulin by the purified IDE. These results raise the possibility that a functional interaction between the insulin and EGF growth factor families can occur which is mediated by the insulin-degrading enzyme.
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PMID:An insulin epidermal growth factor-binding protein from Drosophila has insulin-degrading activity. 249 23

We previously reported on the degradation of monocomponent porcine insulin by affinity-purified pig skeletal muscle insulin-degrading enzyme (IDE) and on the detection and HPLC separation of the initial degradation product (peak VI). Using relatively high concentration of insulin, peak VI appeared rapidly at 30 sec of incubation, whereas other peaks were not detected within 5 min of incubation. Performate oxidation studies suggested that peak VI is composed of a cleaved A-chain and an intact B-chain. To assess whether the initial degradation product of insulin generated by IDE preserves biological properties, we analyzed several insulin-like activities of peak VI. It had a hypoglycemic effect on rats. In vitro, it bound to the insulin receptors of rat adipocytes and stimulated glucose oxidation there. It also strengthened insulin receptor kinase activity in insulin receptors from rat liver and human placenta. Its biological potency, however, was 1/40th to 1/160th that of insulin itself. This is probably due to reduced affinity for the insulin receptor, since it had 2.5% of insulin's ability to both bind to the receptor and stimulate glucose oxidation. Moreover, peak VI had all of insulin's agonistic effect on glucose oxidation when used at a higher concentration. On the other hand, cross-linking analysis suggested that peak VI preserves almost the same affinity for IDE as does insulin. These results suggest that pig skeletal muscle IDE may cleave peptide bonds within the A-chain early in insulin degradation, generating peak VI; this then serves as the next substrate of IDE while exerting reduced insulin-like activity, and peak VI is converted to several relatively low mol wt products.
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PMID:Biological properties of an initial degradation product of insulin by insulin-degrading enzyme. 264 22

An insulin-degrading enzyme has been purified from human erythrocytes. This enzyme degraded 125I-labeled insulin-like growth factor I (IGF-I) more slowly than 125I-IGF-II and degraded IGF-II more slowly than 125I-insulin. The time course of 125I-insulin degradation suggested the presence of intermediates, each of which was itself shown to be a substrate for the enzyme. One of these intermediates appeared to be made up entirely of B-chain residues and had HisB10 as its NH2-terminal. The final major radiolabeled degradation product of A14-[125I]monoiodoinsulin was a peptide with TyrA14 at the A-chain NH2 terminal. This peptide could be reduced with dithiothreitol, suggesting that it contained amino acid residues from both A- and B-chains. It was partially precipitated by trichloroacetic acid and anti-insulin antibody but bound poorly to IM-9 lymphocytes. The final major degradation product of B26-[125I]monoiodoinsulin was a peptide whose NH2-terminal was TyrB26 and could not be reduced by dithiothreitol. It was partially precipitated by anti-insulin antibody but was precipitated poorly, if at all, by trichloroacetic acid and bound poorly to IM-9 lymphocytes. The results show that this enzyme degraded insulin by sequential cleavage of peptide bonds on both A- and B-chains. We identified LeuA13-TyrA14, SerB9-HisB10, and PheB25-TyrB26 as three of the bonds that are cleaved.
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PMID:Degradation of insulin and insulin-like growth factors by enzyme purified from human erythrocytes. Comparison of degradation products observed with A14- and B26-[125I]monoiodoinsulin. 264 37

We have reported the case of a patient whose gallstone was completely fragmented by lithotripsy; all demonstrable particles passed completely within 36 hours. The patient required no analgesics and had no complications from the procedure. This is the first case of gallstones successfully treated solely by a combination of lithotripsy and bile acid therapy in the United States under an FDA-approved IDE protocol.
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PMID:Biliary lithotripsy in the United States. 265 7

The cultured myoblasts of the rat skeletal muscle cell line L6 proliferate till confluency and then fuse to form myotubes and express a number of muscle-specific proteins. We had shown that this differentiation process is blocked by specific metalloendoprotease inhibitors. We now demonstrate that metabolizing L6 myoblasts and their cell extracts degrade insulin to acid-soluble fragments by a non-lysosomal pathway. About 90% of the insulin-degrading activity residues in the cytoplasm and is due to a 110-kDa enzyme known as the insulin-degrading enzyme. The same metalloendoprotease inhibitors that block the differentiation of L6 myoblasts also inhibit insulin degradation by the metabolizing L6 cells, their cell extracts, and the insulin-degrading enzyme immunoprecipitated from the cytosolic extracts by a monoclonal antibody. These results suggest that the insulin-degrading enzyme is the metalloendoprotease whose activity is required for the initiation of the morphological and biochemical differentiation of L6 myoblasts.
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PMID:Metalloendoprotease inhibitors which block the differentiation of L6 myoblasts inhibit insulin degradation by the endogenous insulin-degrading enzyme. 265 90

In Acinetobacter calcoaceticus, a Gram-negative bacterial species, a soluble insulin-degrading proteinase, located in the periplasm as well as in the cytosol, could be established. The periplasmic and cytosolic enzymes agree in their inhibition pattern, pH-optimum and molecular weight. The insulin-degrading enzyme of Acinetobacter calcoaceticus resembles the corresponding proteinases of Escherichia coli. It is a metalloproteinase with a pH-optimum in the neutral range and can be reactivated by divalent ions after EDTA-inhibition, but it is not entirely identical with any of the described proteinases of Escherichia coli in its inhibitory behaviour.
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PMID:Characterization of a periplasmic insulin-cleaving metalloproteinase from Acinetobacter calcoaceticus. 269 74

Combined clinicophysiological investigation was performed in IDE (195 patients) in order to assess the degree of cerebral circulation disorders and their impact on the levels of brain functional activity. The informative values of several quantitative indices of brain hemodynamics and neurodynamics were assessed with respect to the patients' age. Single administration and full course of cavinton and sermion (nicergoline) were effective as judged by cerebral circulation studies (133Xe clearance), brain bioelectric activity (EEG frequency integration analysis, visual evoked potentials). In senile patients, the effect of i.v. sermion administration was dose-dependent.
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PMID:[Initial dyscirculatory encephalopathy in middle-aged and elderly patients (problems of early diagnosis and therapy)]. 271 57

We previously reported on the detection and HPLC separation of the initial degradation product (peak VI) of native insulin from the reaction of monocomponent porcine insulin with affinity-purified pig skeletal muscle insulin-degrading enzyme (IDE). In the present study, we investigated the biological characteristics of the initial degradation product. Structural analysis of peak VI by amino acid composition and glucose oxidation revealed that peak VI was composed of intact B-chain and a fragment of A-chain. In vivo, peak VI exhibited a hypoglycemic effect on rats. In vitro, this peptide had the binding capacity to insulin receptor of rat adipocytes and the ability to stimulate the glucose oxidation on rat adipocytes and the activity of insulin receptor kinase. However, the biological potencies of peak VI were 1/40 to 1/160 of those of insulin proper. Its reduced biological potencies were probably due to a decrease of affinity for insulin receptor, because both biological potencies of peak VI to bind to insulin receptor and to stimulate the glucose oxidation were 2.5% of insulin. Moreover peak VI showed the same full agonistic effect as insulin on the glucose oxidation at higher concentration. On the other hand, a cross-linking study suggested that peak VI preserves almost the same affinity to IDE as insulin. These findings may indicate the possibility that pig skeletal muscle IDE cleaves peptide bonds within A-chain at an early step of degradation of native porcine insulin and generates peak VI, which is the next substrate to insulin for IDE and keeps reduced insulin-like biological potencies, and then peak VI is converted into several relatively low molecular weight products.
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PMID:[Biochemical characteristics of an initial degradation product of insulin by insulin-degrading enzyme]. 285 64

A cytosolic insulin-degrading enzyme (Mr = 110,000) was found to be cross-linked to [125I]-insulin in intact human hepatoma cells, HepG2, incubated with the hormone and treated with the bifunctional cross-linker, disuccinimidyl suberate. The labeling of this protein was greatly increased by concurrent treatment of the cells with N-ethylmaleimide, to the extent that the amount of [125I]-insulin cross-linked to the enzyme in these cells was approximately 20 to 50% that cross-linked to the insulin receptor. The labeling of the insulin-degrading enzyme required the prior interaction of [125I]-insulin with its receptor as well as a temperature- and energy-dependent processing of the hormone. The present work therefore supports a role for this protease in the cellular processing of insulin.
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PMID:In vivo association of [125I]-insulin with a cytosolic insulin-degrading enzyme: detection by covalent cross-linking and immunoprecipitation with a monoclonal antibody. 302 82

After insulin binds to its receptors, insulin-receptor complexes are internalized by absorptive endocytosis, and then insulin seems to be degraded in the intracellular sites. Although the degradation of insulin has been extensively studied, the sites and enzymes of intracellular degradation have still not been appeared. In order to clarify this problem, following experiments were performed. The effects on insulin degradation of the various inhibitors and anti-IDE serum were investigated in isolated rat hepatocytes and Bri-7 human cultured lymphocytes. N-ethylmaleimide and bacitracin, inhibitors which inhibit the activity of insulin-degrading enzyme (IDE), and anti-IDE serum were decreased insulin degradation in Bri-7 cells which does not contain lysosomal pathway. IDE mainly exists in the cytosol fraction, but also on the surface of various cell types. The kinetic changes of insulin receptors and cell surface IDE was determined in Bri-7 cells after preincubation with or without insulin. The concentration of cell surface IDE was determined by immunoenzymatic labeling method using anti-IDE serum. Bri-7 cells were preincubated with 10(-6) M insulin for 30 min to 18 h. Fifty percent of the receptors were lost at 6 h after the preincubation, and level of the receptors achieved a steady state at 18 h. Although the loss of surface IDE was slightly slower than that of receptors, the curves were essentially parallel to each other. Thus, the loss of cell surface receptors and IDE was directly related to the preincubation time. Furthermore, the recovery of decreased surface receptors and IDE was needed for 36 and 72 h, respectively. The alpha-subunit of insulin receptor (135 K) and IDE (110 K) were assessed by cross-linking of 125I-insulin to the plasma membrane and the cytosol of Bri-7 cells, respectively. Cell surface insulin receptor was decreased, whereas cytosolic IDE was increased in Bri-7 cells incubated with insulin. Thus, it is likely that both cell surface and cytosolic IDE, acting either individually or in concert, constitute a physiological mechanism by which the cellular response to insulin is terminated. These results suggest that IDE may play a major role in insulin degradation in the intact cell. Moreover, one possible mechanism of intracellular insulin degradation is that cell surface IDE may be internalized with the insulin receptor complex and may degrade insulin during the intracellular process.
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PMID:[Kinetic studies of insulin degrading enzyme in cultured human lymphocytes]. 304 72


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