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Abstract

Subcellular Components; Preparation and Fractionation G.D. Birnie, ed., 2nd edition, Butteworths, London and University Park Press, Baltimore, 1972; 320 pages, hardbound, $19.50

Methodological Developments in Biochemistry Volume 2 Preparative Techniques E. Reid, ed., Longman, London, 1973; 220 pages; soft cover; $9.50

Methodological Developments in Biochemistry Volume 3 Advances with Zonal Rotors E. Reid, ed., Longman, London, 1973; 273 pages; soft cover; $9.50  相似文献   

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A previous communication from this laboratory1 as well as one from another3 described the separation of α2-macroglobulin from swine serum. The products from both laboratories contained, in addition to α2-macroglob-ulin, an additional macroglobulin contaminant with α2-globulln mobility. Due to their physicochemical similarity these macroglobulins are not resolved using conventional column procedures such as ion exchange chromatography and gel filtration. Subsequent experiments have shown that immunoelectro-phoretically pure swine α2-macroglobulln is present, in good yield (65%) in the breakthrough effluent of columns of Bio-Gel A-1.5m-Reactive Blue 2 while the contaminating macroglobulin is tightly bound. The production of highly purified swine α2-macroglobulin utilizing this observation is the subject of the present report. The product of the separation was found to be homogeneous when subjected to Immunoelectrophoresis, at a concentration of 14–16 mg/ml, and diffused against antiswlne whole serum antibody. The production of monospecific antibody, a more stringent test for homogeneity, resulted when the purified α2-macroglobulin was injected into rabbits. Physicochemical analyses on the purified product showed that swine and human α2-macro-globulins are true homologs.  相似文献   

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When calf rennet containing ~ 15% pepsin was applied to a Cibacron Blue agarose column at pH 5.5 in a low salt medium, pepsin passed through unadsorhed while chymosin was bound to the gel in the column. After washing the column, the bound chymosin was eluted with 1.7 M NaCl or 50% (v/v) aqueous ethylene glycol. The salt eluate was analyzed and found to contain > 97% pure chymosin. The fraction that passed through unadsorbed was found to contain > 96% pure pepsin. Thus a complete separation of chymosin and pepsin was effected by this technique without having to destroy either enzvme. Both enzymes are highly negatively charged at pH 5.5 but the separation does not arise from anion exchange since the gel functions as a cation exchanger. The separation appears to result from a combination of hydrophobic and electrostatic interactions of chymosin with Blue agarose. It is suggested that the enhanced affinity of chymosin to the Blue gel over pepsin may arise from topographically specified interaction between chymosin and the blue chromophore. Differential surface hydrophobicity may also play a key role, since in the presence of 0.7 M Na2SO4 the same behavior as at low ionic strength is observed.  相似文献   

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An ionically unbound and thermostable polyphenol oxidase (PPO) was extracted from the leaf of Musa paradisiaca. The enzyme was purified 2.54-fold with a total yield of 9.5% by ammonium sulfate precipitation followed by Sephadex G-100 gel filtration chromatography. The purified enzyme exhibited a clear single band on native polyacrylamide gel electrophoresis (PAGE) and sodium dodecyl sulfate (SDS) PAGE. It was found to be monomeric protein with molecular mass of about 40 kD. The zymographic study using crude extract as enzyme source showed a very clear band around 40 kD and a faint band at around 15 kD, which might be isozymes. The enzyme was optimally active at pH 7.0 and 50°C temperature. The enzyme was active in wide range of pH (4.0–9.0) and temperature (30–90°C). From the thermal inactivation studies in the range 60–75°C, the half-life (t1/2) values of the enzyme ranged from 17 to 77 min. The inactivation energy (Ea) value of PPO was estimated to be 91.3 kJ mol?1. It showed higher specificity with catechol (Km = 8 mM) as compared to 4-methylcatechol (Km = 10 mM). Among metal ions and reagents tested, Cu2+, Fe2+, Hg2+, Mn2+, Ni2+, protocatechuic acid, and ferrulic acid enhanced the enzyme activity, while K+, Na+, Co2+, kojic acid, ascorbic acid, ethylenediamine tetraacetic acid (EDTA), sodium azide, β-mercaptoethanol, and L-cysteine inhibited the activity of the enzyme.  相似文献   

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ABSTRACT

Covalent structural information on membrane proteins is not easily acquired since it is difficult to obtain pure membrane proteins in sufficient quantities. We have therefore examined the Bio-Rad 491 prep cell continuous elution electrophoresis apparatus as a method for providing the quantities of purified , alpha and beta subunits from (Na.K)-ATPase required for these studies. Twenty-four milligrams of crude (Na.K)-ATPase preparation was applied to the prep cell which consisted of a 7% Laemmli separating gel 4.5 cm in length. The prep cell was Y run under constant power and continuous cooling conditions. Those fractions containing the beta subunit were combined and further purified by wheat germ agglutinin affinity"' chromatography. Fractions containing the alpha subunit were combined and did not require further purification. The identity and the degree of purity of the proteins obtained using this approach was assessed utilizing SDS-PAGE, amino acid analysis 375 Copyright 1993 by Marcel Dekker, Inc. * and N-tertninal sequencing. This simple and fast method provides approximately 1.8 milligrams of each purified subunit from 24 milligrams of relatively crude microsomes. Recovery of the alpha and beta subunits from the crude (Na.K)-ATPase preparation was estimated to be 28% and 81%, respectively.  相似文献   

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Two MMP-7-ase isoenzymes were purified 100-fold from rat muscle extract to apparent homogeneity, with an overall yield of 10%, using homogenization, ultracentrifugation, high-performance aqueous size-exclusion and high-performance anion exchange chromatography methods. When using a TSK G-2000SW column, the separation resulted in a 6-fold purification and 30% recovery of isoenzymes B and C. This concentrated enzyme extract was then passed through a TSK-DEAE-2SW column, using salt gradient at pH 7.5, with an additional 25-fold purification and 90% recovery of the isoenzymes. Two symmetrical enzyme peaks, representing isoenzymes B and C, were detected when performing purity tests of the active enzymes on the anion exchanger and reversed-phase HFLC columns. The procedures involved are extraction, ultracentri-fugation, chromatographies and enzyme assays and require less than five hours.  相似文献   

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Abstract

A series of 3,4‐dihydropyrimidin‐2‐(1H)‐ones compounds was synthesized efficiently by a one‐pot cyclocondensation of an aldehyde, 1,3‐dicarbonyl compound, and urea in absolute ethanol under refluxing temperature using praseodymium methanesulfonate as catalyst. After the reaction, the catalyst can be easily recovered and reused several times without distinct decrease in reaction yields.  相似文献   

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Formycin B [9-deazainosine] was reacted with epoxy-activated Sepharose 68 to form an affinity resin for purine nucleoside phosphorylase (PNPase). This resin had a large capacity (7,600 units/ml) for the enzyme from Escherichia coli. Enzyme retention was dependent on high ionic strength. Although this property is reminiscent of hydrophobic interaction chromatography, analogous resins prepared with pseudouridine or monoethanolamine instead of with formycin B, did not retain the enzyme even at high ionic strength. Furthermore, hypoxanthine facilitated elution of the enzyme from the resin. It appeared, therefore, that the enzyme was not bound simply by hydrophobia interactions. A simple two-step purification procedure for PNPase from Escherichia coli was devised using this resin. Overall recovery was 50%, and purity of the final preparation was greater than 95%. This resin was also useful in the purification of PNPase from human erythrocytes. The ether linkage between formycin B and Sepharose 6B, together with the carbon-to-carbon linkage between the pentose and heterocyclic moieties of formycin B, provided stability to both chemical and enzymatic degradation. After 5 years of use and exposure to a variety of biological preparations, the resin showed no detectable decrease in its ability to bind PNPase.  相似文献   

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A device of a new dish for the culturing of cells on a biological substrate, the eye lens capsule, is described. With the aid of this dish it is possible to investigate the possible interrelationships between the cell substratum and various biochemical characteristics of the cell. It is shown that the protein biosynthetic pattern differs between lens cells cultured on lens capsule as a substrate and cells cultured on foil. Moreover, the new dish opens the possibility to culture epithelial cells on a lens capsule, which gives an alternative to the culture of these cells on a collagen substrate.  相似文献   

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[BPy]H2PO4 was easily prepared and used as an efficient and recyclable catalyst for the one-pot synthesis of 2,4,5-trisubstituted imidazoles under solvent-free conditions in good to excellent yields. Solvent-free conditions, simple experimental and workup procedures, and the use of a nontoxic, recyclable catalyst of an environmentally benign nature are remarkable features of the procedure.  相似文献   

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