Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.26.9 (ribonuclease)
 6,589 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A quick and simple method has been developed for the recovery of proteins from water-in-oil microemulsions (w/o-MEs), which is needed to further the use of liquid-liquid extraction in bioseparations. By adding a small portion (0.1 v/v or less) of cosurfactant (e.g., 1-alkanol) to w/o-ME solution, proteins were readily expelled, sometimes as solids, while most or all of the surfactant (Aerosol OT) remained in solution. The release of proteins increased with the further addition of cosurfactant and was greater when the molar ratio of protein to w/o-ME or fractional occupancy (f) was high. However, protein expulsion was also significant when f was small. The addition of cosurfactant released ribonuclease, lysozyme, alpha-chymotrypsin, pepsin, bovine serum albumin (BSA), and catalase from w/o-ME solution, but the expulsion was greater for BSA relative to chymotrypsin and lysozyme. Protein expulsion also increased with cosurfactant chain length for the homologous series of 1-alkanols starting at 1-butanol; however, water was also coexpelled in significant amounts. An exception to the latter rule was 1-butanol, which readily promoted the release of protein, but not encapsulated water. The addition of 1-butanol to a w/o-ME solution containing alpha-chymotrypsin and BSA selectively released the former protein, with chymotryptic activity occurring in the recovered protein. Possible mechanisms for the cosurfactant-mediated release of protein are discussed. Copyright 1998 John Wiley & Sons, Inc.
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PMID:Expulsion of proteins from water-in-oil microemulsions by treatment with cosurfactant 1009 72

Previous studies from this laboratory have demonstrated that administration of the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) to pregnant hamsters results in tumors in the offspring. Whereas treatment with NNK alone caused mainly tumors in the respiratory tract of the treated offspring, cotreatment with ethanol (EtOH) and NNK shifted the site of tumor formation to the pancreas. In order to determine potential mechanisms for the cocarcinogenic effects of EtOH, the levels of NNK metabolites and expression of various CYPs implicated in the metabolic activation of NNK were determined in fetal liver and pancreas. NNK and its metabolite, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), were detected at low and variable levels in the fetal liver and pancreas, with an NNAL to NNK ratio greater than 20 in both organs. EtOH had no effect on the amount of metabolites found in either organ. Results obtained with the fetal liver samples, which served as a positive control, correlated very well with our previous studies demonstrating low levels of expression of several CYP isozymes at both the protein and RNA level. Western blot analysis showed low but detectable levels of CYP1A1, barely detectable levels of CYP2E1, and an absence of CYP1A2 and 2B family members in the fetal pancreas. RNA transcripts were undetectable by ribonuclease protection in the fetal pancreas, although readily seen in fetal liver samples. Treatment with NNK, EtOH, or both NNK and EtOH had small and variable effects on the levels of metabolism of NNK and expression of the isozymes. These findings suggest that alternative mechanisms may be responsible for transplacentally induced tumors in this model system.
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PMID:Low levels of expression of cytochromes P-450 in normal and cancerous fetal pancreatic tissues of hamsters treated with NNK and/or ethanol. 1091 Sep 89

As a means of preparing N-linked oligosaccharides from hydrazinolysates of glycoproteins in a rapid and simple manner, a method has been developed using cellulose-column chromatography. Hydrazinolysates of human IgG, containing a series of biantennary complex type oligosaccharides, were applied to a cellulose column equilibrated with (4:1:1, v/v) 1-butanol-ethanol-water. The N-linked oligosaccharides were eluted with (1:1, v/v) ethanol-water, and analyzed by HPLC in combination with sequential glycosidase digestion. The oligosaccharides, with or without sialic acid, were quantitatively recovered in the fraction eluted with (1:1, v/v) ethanol-water without UV-detectable contamination by impurities derived from protein or the cellulose. Other types of N-linked oligosaccharides of alpha1-acid glycoprotein (tetraantennary complex-type), ovalbumin (hybrid-type), and ribonuclease B (high mannose-type) were also quantitatively prepared from the hydrazinolysates by elution of the cellulose column with (1:1, v/v) ethanol-water and these had as high a quality as those prepared by conventional paper chromatography.
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PMID:Rapid and simple preparation of N-linked oligosaccharides by cellulose-column chromatography. 1143 95