Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.21.1 (chymotrypsin)
10,938 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In 11 juvenile diabetics and 13 control subjects, the secretin-pancreozymin test was performed. Duodenal-volume losses were corrected by use of radioactive vitamin B12 as marker substance. As compared to normal subjects, juvenile diabetics had significantly decreased pancreatic outputs of amylase, trypsin, chymotrypsin, and to a lesser degree, of bicarbonate. Clinical evidence of disease of the exocrine pancreas was missing. There was no discernible relationship between the abnormality of external pancreatic function and the duration of diabetes mellitus or the dose of insulin required. Possible factors that may be responsible for the exocrine deficiency of the pancreas in juvenile diabetics are discussed.
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PMID:Exocrine pancreatic function in juvenile diabetics. 113 Mar 59

The experiments reported here indicate that, when exposed to insulin, viable lymphocytes rapidly released into the incubation medium a factor capable of increasing the dextran-induced anaphylactoid reaction, but having no effect on the inflammatory response evoked by 5-HT. This pro-inflammatory factor was shown to be elaborated by cell suspensions derived from lymph nodes of rats, rabbits, pigs or calves as well as from human tonsils. Thymus cells showed no such activity. The pro-inflammatory factor was termed as anaphylactoid-inflammation-promoting factor (AIPF). Its production depended upon the dose of insulin, and the time of exposure. AIPF was found to have an elution pattern in Sephadex G-100 gels similar to that of BSA (67,000 daltons). The activity was abolished by heat or incubation with DNase or a-chymotrypsin, but was not influenced by RNase. AIPF by itself did not induce increased vascular permeability, and proved to be distinct from the permeability factors present in the lysate of lymph node cells.
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PMID:Anaphylactoid-inflammation-promoting factor. An insulin-induced factor derived from non-sensitized lymphocytes increases anaphylactoid inflammation in rats. 115 Mar 30

The amino acid sequence of the proinsulin C-peptide isolated from guinea pig pancreas was determined and experimental data are presented. Digestion of the C-peptide with chymotrypsin provided two dodecapeptides, a tetrapeptide, and glutamine, which account for the intact chain. Reaction of the C-peptide with cyanogen bromide resulted in cleavage at the single methionine and provided two additional fragments. Digestion of the large peptides with papain provided a variety of small peptides and the complete sequence was assigned by identification of the fragments. Although guinea pig insulin differs markedly from mammalian insulins, guinea pig C-peptide has many features of primary structure in common with the C-peptides of other mammals. The conservation of specific residues in C-peptides indicates that these residues form essential elements in the three-dimensional structure of proinsulin.
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PMID:Guinea pig proinsulin. Primary structure of the C-peptide isolated from pancreas. 115 64

Insulin stimulated the tyrosine phosphorylation of a 61-kilodalton (kDa) protein in rat adipocytes prelabeled for 2 h with [32P]orthophosphate. Tyrosine phosphorylation of this 61-kDa protein displayed very similar insulin concentration dependency to receptor autophosphorylation and tyrosine phosphorylation of a high molecular mass receptor substrate of 160 kDa. Phosphorylation of the 61-kDa protein was very rapid with maximum labeling attained at 30 sec, paralleling that of the other two proteins. Phosphoamino acid analysis revealed that each of the insulin-responsive phosphoproteins contained phosphoserine as well as phosphotyrosine, though the ratio of two phosphoamino acids recovered from each protein differed. The 61-kDa protein yielded relatively equal proportions of phosphoserine and phosphotyrosine. In contrast, the insulin receptor yielded relatively more label on phosphotyrosine than phosphoserine, whereas label incorporated into the 160-kDa protein was recovered primarily on phosphoserine. Cleveland peptide maps using either Staphylococcus aureus V8 proteinase or chymotrypsin revealed no similarities between the 61-kDa protein and the other tyrosine phosphorylated proteins. With subcellular fractionation, the 160-kDa protein was found in equal proportions in the high speed pellet (100,000 g) and supernatant. The 61-kDa protein had a similar distribution to that of the 160-kDa protein but was also detected in the low speed pellet (10,000 g). The insulin receptor was localized to the low speed pellet. In summary, rat adipocytes contain an insulin-dependent phosphotyrosyl protein of 61 kDa which is distinct from the more prominent high molecular mass receptor substrate. This 61-kDa protein has characteristics consistent with it being a substrate for the insulin receptor tyrosine kinase.
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PMID:Insulin stimulates the tyrosine phosphorylation of a 61-kilodalton protein in rat adipocytes. 137 54

A proteinase was purified to electrophoretic homogeneity from crude extracts of the thermoacidophilic archaebacterium Sulfolobus solfataricus. Molecular mass values assessed by SDS-PAGE and gel filtration were 54 and 118 kDa, respectively, which points to a dimeric structure of the molecule. An isoelectric point of 5.6 was also determined. The enzyme behaved as a chymotrypsin-like serine proteinase, as shown by the inhibitory effects exerted by phenylmethanesulfonyl fluoride, 3,4-dichloroisocoumarin, tosylphenylalaninechloromethyl ketone and chymostatin. Consistently with the inhibition pattern, the enzyme cleaved chromogenic substrates at the carboxyl side of aromatic or bulky aliphatic amino acids; however, it effectively attacked only a small number of such substrates, thus, displaying a specificity much narrower than and clearly different from that of chymotrypsin. This was confirmed by its inability to digest a set of natural substrate proteins, as well as insulin chains A and B; only after alkylation casein was degraded to some extent. Proteinase activity was significantly stimulated by Mn2+ which acted as a mixed-type nonessential activator. The enzyme also displayed a broad pH optimum in the range 6.5-8.0. Furthermore, it was completely stable up to 90 degrees C; above this temperature it underwent first-order thermal inactivation with half-lives ranging from 342 min (92 degrees C) to 7 min (101 degrees C). At 50 degrees C it could withstand 6 M urea and, to some extent, different organic solvents; however, at 95 degrees C it was extensively inactivated by all of these compounds. None of the chemical physical properties of the enzyme, including amino-acid analysis, provided evidence of a possible relation to other well-known microbial serine proteinases.
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PMID:A heat-stable serine proteinase from the extreme thermophilic archaebacterium Sulfolobus solfataricus. 150 89

Cells of Acinetobacter calcoaceticus contain a constitutive periplasmic metalloproteinase showing similar properties as the periplasmic metalloproteinase of Escherichia coli. The periplasmic proteinase of A. calcoaceticus was purified, starting from periplasm, by ammonium sulfate precipitation, hydrophobic interaction chromatography and chromatofocusing up to the homogeneity of the enzyme in SDS-electrophoresis with a yield of 6.7% and a purification factor of 417. The enzyme has a molecular mass of 108,000 (gel filtration) or 112,000 (native electrophoresis), and consists of four identical subunits with a molecular mass of 27,000 (SDS-electrophoresis). The purified enzyme degrades preferentially polypeptides such as glucagon and insulin. Larger proteins are accepted as substrates to a considerably lower extent. All tested synthetic substrates with trypsin, chymotrypsin, elastase and thermolysin specificity were not cleaved. Therefore, the described enzyme was designated "insulin-cleaving proteinase" (ICP).
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PMID:Purification of a periplasmic insulin-cleaving proteinase from Acinetobacter calcoaceticus. 151 May 71

Qualitative disorders of an echopancreatogram are noted in half of patients with diabetes mellitus (both insulin dependent and noninsulin dependent). The most significant echopancreatographic quantitative and qualitative disorders were observed in diabetic patients with a maximal decrease in pancreatic enzyme excreting activity (on the basis of lipase and trypsin debit in a pancreozymin test, daily steatorrhea and chymotrypsin amount in daily feces). It has been assumed that a degree of ultrasound changes in the pancreas in diabetes depends on a degree of fibrosis of pancreatic exocrine tissue. Ultrasound investigations with quantitative and qualitative assessment of echopancreatograms is a valuable adjuvant diagnostic method in diabetes mellitus.
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PMID:[Echostructure of the pancreas. Comparison with exocrine secretory activity of the pancreas in patients with diabetes mellitus]. 151 83

In a previous study (Frazier et al., 1990), it was demonstrated that two patients with type 1 (insulin-dependent) diabetes mellitus had antibodies in their serum which reacted with four 29 kDa pancreas-specific proteins on two-dimensional immunoblots. This paper reports on the purification and identification of these pancreatic proteins. The protein with the pI closest to pH7 was purified through the use of ammonium sulfate fractionation and ion-exchange chromatography. Gel filtration chromatography established that the protein's molecular weight was closer to 25 kDa. Amino acid composition and sequence analyses demonstrated homology between the protein and chymotrypsin. It is suggested that an abnormal regulation of chymotrypsin activity might be related to antibodies formed in some diabetic patients.
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PMID:Chymotrypsin-reactive antibodies in insulin-dependent diabetes mellitus. 158 8

A small redox-active protein has been purified to homogeneity from cell-free extracts of the strictly anaerobic thermophilic methanogen, Methanobacterium thermoautotrophicum (strain Marburg). The purification consisted of streptomycin sulfate and acid treatments and three chromatographic steps using Sephadex G-75, Mono Q HR 10/10, and Superose 12 HR 10/30 columns. When these procedures were carried out under strictly anaerobic conditions, approximately 3 mg of this protein could be isolated from 45 g of wet cell paste. Like the thioredoxins and glutaredoxins, it is a small acidic protein (pI = 4.2) consisting of 83 amino acids (M(r) = 9136). In the presence of dithiothreitol or dihydrolipoate, the protein serves as a hydrogen donor for the ribonucleotide reductase from Escherichia coli, and it catalyzes the reduction of insulin. However, it does not interact with the thioredoxin reductases from E. coli or Corynebacterium nephridii and does not function as a hydrogen donor for the ribonucleotide reductase of C. nephridii. The amino acid sequences determined by automated Edman degradation of the 14C-carboxymethylated protein and of peptides derived from trypsin and chymotrypsin digestions show a redox-active site -Cys-Pro-Tyr-Cys-, typical of the glutaredoxins. Its amino acid sequence shows moderate identity with the known glutaredoxins (E. coli, yeast, rabbit bone marrow, calf thymus, and pig liver) when the proteins are aligned at the active site. The secondary structure of the glutaredoxin-like protein predicted by the Chou-Fasman procedure shows that it is similar to the known glutaredoxins. However, surprisingly, the protein does not function as a glutathione-disulfide oxidoreductase in the presence of glutathione and glutathione reductase. This glutaredoxin-like protein may be a component of a ribonucleotide-reducing system distinct from the previously described systems utilizing thioredoxin or glutaredoxin.
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PMID:The purification, characterization, and primary structure of a small redox protein from Methanobacterium thermoautotrophicum, an archaebacterium. 158 36

Isobutylcyanoacrylate nanocapsules have been used as drug carriers for the enteral absorption of insulin. Their absorption has been studied by measuring fasted glycaemia in streptozotocin-induced diabetic rats after a single administration of encapsulated insulin (100 units kg-1) at various sites along the gastrointestinal tract. Glycaemia decreased from the second day, the intensity and duration depending on the site of administration (65% ileum, 59% stomach, 52% duodenum and jejunum, 34% colon). This hypoglycaemic effect lasted up to the 18th day after administration for ileum and jejunum, the 15th day for stomach and duodenum, and the 13th day for colon. In-vitro, nanocapsules protect insulin against proteolysis from pepsin, chymotrypsin and trypsin. These results suggest (i) that insulin is protected by nanocapsules in the gastrointestinal tract, (ii) that it is absorbed in an active form, and (iii) that ileum is the most potent site of absorption.
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PMID:The effect of site of administration in the gastrointestinal tract on the absorption of insulin from nanocapsules in diabetic rats. 167 51


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