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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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Increasing complications in incisional hernia surgery call for novel treatments. A gene expression analysis of injured tissues displays important parameters for tissue regeneration. Until today, no reliable method has been described for a quantitative gene expression analysis of hernia tissues. In this work, a protocol is described for the isolation of DNA‐free total RNA of incisional hernias for the first time. Moreover, real‐time RT PCR assays for collagen type I and III and TGF‐β1 are demonstrated for relative gene expression analyses. Both methods enable relative gene expression analyses of hernia tissues for the first time.  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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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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