Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Some variants of the quantitative dansyl method in combination with thin-layer chromatography on polyamide plates have been compared, and principles of its optimization have been demonstrated. Sensitivity of the method is about 10(-11) mole, the error does not exceed 10%. Data are given on the analysis by the dansyl method of peptides of the tryptic hydrolysate of bovine pancreatic ribonuclease after their separation by peptide mapping procedure.
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PMID:[Quantitative dansyl micromethod of amino acid analysis. Study of peptide maps of ribonuclease tryptic hydrolysate]. 56 40

Ribonucleases are found in considerable quantities in the pancreas of a number of mammalian taxa and a few reptiles. The ribonuclease content varies greatly in different species. Large quantities are found in ruminants and species that have a ruminant-like digestion and in a number of species with coecal digestion. This is a response to the necessity of digesting large amounts of RNA derived from the microflora of the stomach of ruminants or species with ruminant-like digestion or of the coecum of species with coecal digestion. The amino acid sequence of pancreatic ribonuclease from the chromosomal species 2n = 60 of the mole rat, superspecies Spalax Ehrenbergi was determined. From the comparison of the sequence with those of other mammalian species we found that Spalax diverged from the myomorph rodent branch before the divergence of the Muridae (mouse, rat) from the Cricetidae (hamster, muskrat). Spalax ribonuclease shares several amino acid residues with other myomorph rodent species. These are not or only rarely observed outside this rodent suborder. Although the ribonuclease content varies greatly in different mammalian species, the variation in content between individuals within a species is small. Spalax is an exception to this with ribonuclease contents varying over more than an order of magnitude in different individuals. Ribonucleases isolated from the chromosomal species 2n = 52, 2n = 58 and 2n = 60 have identical elution positions on reversed-phase HPLC. The enzyme from the 2n = 54 species, however, elutes at a slightly earlier elution position. No amino acid sequence differences have been found hitherto between the ribonucleases of the four chromosomal species of Spalax ehrenbergi occurring in Israel. However, due to lack of material we were unable to determine more than about 20% of the sequence of the enzyme from the 2n = 54 species, which is the oldest offshoot.
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PMID:Ribonuclease in different chromosomal species of the mole rat, superspecies Spalax ehrenbergi: concentration in the pancreas and primary structure. 230 13

The isoelectric point (pI) value of 3-mercaptopyruvate sulfurtransferase (MST) from human erythrocytes was determined to be 6.3 at 10 degrees C by isoelectric focusing in horizontal slab polyacrylamide gel containing 2% carrier ampholyte (pH 3-10). The value was determined by comparison with the electrofocused bands of bovine pancreatic ribonuclease A-glutathione mixed disulfides (RNase-SG), which were composed of 8 species containing 1 (RNase-SG1) through 8 (RNase-SG8) moles of glutathione per mole of ribonuclease A with different pI values ranging from 5.3 (RNase-SG8) to 8.8 (RNase-SG1). The pI value of the same enzyme in a 110,000 X g supernatant of rat liver was 5.9, which was the same as that of rat erythrocyte enzyme. Treatments of rat hemolysate with oxidized glutathione or diamide resulted in a shift of the pI of MST to a lower value, 5.7-5.5. This shift was inhibited when these treatments were performed in the presence of dithiothreitol. These results indicate that the treatment of the enzyme with oxidized glutathione results in the formation of enzyme-glutathione mixed disulfide.
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PMID:Determination of the isoelectric point value of 3-mercaptopyruvate sulfurtransferase and its shift by treatment with oxidized glutathione. 271 69

We measured the excretion rates of six urinary enzymes that either originate from the proximal renal tubule, like alanine aminopeptidase (EC 3.4.11.2), alkaline phosphatase (EC 3.1.3.1), gamma-glutamyltransferase (EC 2.3.2.2), and N-acetyl-beta-D-glucosaminidase (EC 3.2.1.30), or that are typical low-molecular-mass proteins, like lysozyme (EC 3.2.1.17) and pancreatic ribonuclease (EC 3.1.27.5). These rates were compared with those of total protein and albumin in urine of 36 insulin-dependent diabetic men and 30 healthy men. Seventeen of the diabetics had "clinical proteinuria," defined as excretion of more than 7.5 g of protein per mole of urinary creatinine (group B). Group A comprised the 19 diabetics without proteinuria. Except for gamma-glutamyltransferase, the excretions of enzymes and proteins were significantly higher in diabetics than in controls and were greater in group B than in group A. N-Acetyl-beta-D-glucosaminidase was the analyte most often increased in group A (89%), followed by albumin and alkaline phosphatase (each 32%). All patients in group B showed increased excretion of N-acetyl-beta-D-glucosaminidase. We conclude from the comparative data that this enzyme may be useful as an early predictor of diabetic nephropathy.
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PMID:Urinary enzymes and low-molecular-mass proteins as indicators of diabetic nephropathy. 289 6

A 30-residue peptide was obtained from ribonuclease A by chemical cleavage with cyanogen bromide, subsequent sulfitolysis with concomitant S-sulfonation, and finally enzymatic cleavage with Staphylococcus aureus protease. The peptide was converted to the free thiol form by reductive cleavage of the S-sulfo-protecting groups with D,L-dithiothreitol. This peptide consisted of residues 50-79 of the native sequence of ribonuclease A, with the exception that methionine-79 had been converted to homoserine. Included in this sequence are residues cysteine-65 and cysteine-72, which form a disulfide bond in the native enzyme, as well as cysteine-58. This molecule may form one of three possible intramolecular disulfide bonds upon thiol oxidation, viz. one loop of 15 and 2 of 8 residues each. These isomeric peptides were prepared by oxidation with cystamine, 2-aminoethanethiolation of residual thiols, and fractionation by reverse-phase high-performance liquid chromatography. Disulfide pairings were established by mapping the tryptic fragments and confirming their composition by amino acid analysis. After protracted incubation under oxidizing conditions at 25.0 degrees C and pH 8.0, the 26-member ring incorporating the native disulfide bond between residues 65 and 72 is the dominant product. Assuming that equilibrium is established, we infer that local interactions in the sequence of ribonuclease A significantly stabilize the native 8-residue disulfide loop with respect to the non-native 8-residue loop (delta G degree = -1.1 +/- 0.1 kcal mole-1). The implications of this observation for the oxidative folding of the intact protein are discussed.
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PMID:Local interactions favor the native 8-residue disulfide loop in the oxidation of a fragment corresponding to the sequence Ser-50-Met-79 derived from bovine pancreatic ribonuclease A. 325 71

The pI value of rat erythrocyte 3-mercaptopyruvate sulfurtransferase (EC 2.8.1.2) was determined to be 5.9 at 10 degrees C by isoelectric focusing in a horizontal slab polyacrylamide gel containing 2% carrier ampholyte (pH 3-10). In this study, ribonuclease A-glutathione mixed disulfides (RNase-SG's) (T. Ubuka et al. (1986) J. Chromatogr., 363, 431-437) were used as pI standards. A mixture of RNase-SG was prepared by reducing bovine pancreatic ribonuclease A (RNase) with dithiothreitol and then treating the reduced RNase with oxidized glutathione. The mixture was composed of eight species which contained 1 (RNase-SG1) to 8 (RNase-SG8) mol of glutathione per mole of RNase, and the pI values of these species were determined under conditions minimizing the effect of carbon dioxide. The newly determined pI values of RNase-SG1 through RNase-SG8 were 8.8, 8.2, 7.7, 7.3, 6.9, 6.4, 5.8, and 5.3, respectively. The average change in pI values of these disulfides was 0.50 pH unit per mole of the bound glutathione per mole of RNase. The RNase-SG mixture was stable in acidic solutions and could be stored at 4 degrees C as well as at -20 degrees C with little change for at least 1 year. Thus, the mixture is shown to be an excellent standard for the determination of pI values of proteins by isoelectric focusing in the wide range of pI value.
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PMID:Determination of isoelectric point value of 3-mercaptopyruvate sulfurtransferase by isoelectric focusing using ribonuclease A-glutathione mixed disulfides as standards. 348 77

The capacity of bovine serum amineoxidase (SAO) to oxidize free amino groups of nonconventional substrates, such as polylysine (up to 50 kDa) and some proteins as lysozyme and ribonuclease A, is described. The oxidation was quantified from the amount of H2O2 and NH3 enzymatically produced by SAO. Kinetic analysis indicated a stereospecific preference for L-configuration. Maximal oxidation rate was obtained with poly-L-lysine (9.6 kDa). After 10 h of incubation at 37 degrees C, the poly-L-lysine was partially oxidized generating 1.5 moles of H2O2 by one mole of polylysine. Denatured SAO presented very low oxidation rates with the mentioned substrates.
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PMID:Extended substrate specificity of serum amine oxidase: possible involvement in protein posttranslational modification. 866 Mar 85

Renaturation of modified ribonuclease A by protein disulfide isomerase was studied. The renaturation rate of fully S-thiolated ribonuclease A with glutathione, namely, ribonuclease A-glutathione mixed disulfide (RNase-SG) containing 8 moles of glutathione per mole of ribonuclease A (RNase-SG8), by protein disulfied isomerase (PDI) was more than three times faster than those of fully S-thiolated RNase with L-cysteine and scrambled ribonuclease A. Renaturation of RNase-SG species containing 7 or less glutathione was slower than that of RNase-SG8. These data seems to favor the hypothesis that S-thiolation of nascent proteins with glutathione may occur in the folding process during protein synthesis. The applicability of the present method consisted of chemical S-thiolation and PDI-catalyzed renaturation to the in vitro folding of recombinant cysteine-containing proteins is discussed.
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PMID:Protein disulfide isomerase-catalyzed renaturation of ribonuclease A modified by S-thiolation with glutathione and cysteine. 873 31

Two different theories based on a multiple equilibrium model for analysing the binding data for ionic surfactant-protein interactions are investigated and modified, and intrinsic and statistical Gibbs free energies of binding per mole of surfactant are estimated. The characterization of the two models and interpretation of the binding process in terms of intrinsic and statistical binding free energies are discussed. These theories are applied to analysis of sodium n-dodecyl sulfate binding to ribonuclease A and lysozyme. Copyright 1997Academic Press
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PMID:Statistical Effects of the Binding of Ionic Surfactant to Protein 936 64

Spectrophotometric profiles representing the unfolding induced by guanidine on Bothrops moojeni myotoxins-I (MjTX-I) and II (MjTX-II), Bothrops jararacussu bothropstoxin-I (BthTX-I) and Bothrops pirajai piratoxin-I (PrTX-I) were obtained and compared with those obtained with bovine ribonuclease A (RNAse) and trypsin. The molar (epsilon(1M)) and percent (epsilon(1%)) extinction coefficients were determined for the four myotoxins as well as for RNAse and trypsin as reference parameters. These coefficients were then used throughout this work. The changes in free energy (deltaGD(H)(2)(O)) corresponding to zero guanidine concentration and the guanidine concentrations (D(1/2)) able to convert 50% of the molecules from the native to the unfolded state were determined. The values of deltaGD (H)(2)(O) ranged from 4.42 (BthTX-I) to 8.02 (MjTX-I) kcal/mole, compared with 6.47 and 6.88 kcal/mole for trypsin and RNAse, respectively. The values for deltaGD(H)(2)(O) and D1/2 showed that BthTX-I is the least stable among the four myotoxins assayed, with a D1/2 close to that of RNAse, while MjTX-II is conformationally the most stable. Monitoring of the unfolding of RNAse and PrTX-I by a 0 to 6 M urea gradient PAGE revealed transitions from the native (N) to the unfolded (U) state with deltaG(N-U)of 0.22 and 0.41 kcal/mole, respectively. Sigmoidal curves showed well-defined two-stage transitions for both proteins.
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PMID:Spectroscopic analysis of the stability of bothrops myotoxic phospholipases A2 to guanidine and urea denaturation. 1262 31


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