Micrococcus lysodeikticus

All earlier studies [155-158] reported the complexation of berberine with calf thymus DNA and suggested by a mechanism of intercalation. Maiti and coworkers [159-162] demonstrated first the base- and sequence-specificity of berberine from studies with several naturally occurring DNAs (Clostridium perfringenes, cholera bacteriophage 02, calf thymus, Escherichia coli, Micrococcus lysodeikticus) and synthetic DNAs ((poly(dG-dC) poly(dG-dC), poly(dG)-poly(dC), poly(dA-dT) poly(dA-dT), poly(dA)-poly(dT)) using various physicochemical techniques. Several aspects of the interaction were reported ... 

Owen P, Salton MRJ (1975) Succinylated mannan in membrane system of Micrococcus-lysodeikticus. Biochem Biophys Res Commun 63 875-880... 

Pless DD, Schmit AS, Lennarz WJ (1975) The characterization of mannan of Micrococcus lysodeikticus as an acidic lipopolysaccharide. J Biol Chem 250 1319-1327... 

An agar dilution assay using Micrococcus lysodeikticus has been reported130. 

Ceriotti has reported an agar diffusion assay for gramicidin utilizing Micrococcus lysodeikticus 1. ... 

The most amplified amine, 22b, was resynthesized and assayed against the rate of HEWL lysis of Micrococcus lysodeikticus. Competitive inhibition kinetics was observed, with a recorded K value of 0.6 mM. The... 

Catalase from Micrococcus lysodeikticus provides a rare example of water coordinated directly to heme-iron (Fe—O = 2.28 A). This ligand water is hydrogen-bonded to another water molecule resident in the heme pocket. ... 

Enzymic Activity. Lysozyme activity was determined by following the rate of lysis of dried Micrococcus lysodeikticus cells according to the method of Shugar ( ). Assays were run at room temperature in O.IM phosphate buffer pH 7.0, with an enzyme concentration of about 0.05 mg/ml. A solution of native lysoz3mie at the same protein concentration was always assayed as standard, along with ozonized lysozymes. 

Uridine 5 -(2-acetamido-2-deoxy-a-n-gIucopyranosyluronic acid pyrophosphate) (36) was isolated from extracts of Achromobacter georgiopolitanum14Sa and Micrococcus lysodeikticus.149b The ester of uridine 5 -pyrophosphate with an unusual amino sugar, namely, a 2-acetamido-2,4,6-trideoxyhexose of unknown configuration, has... 

Lysozyme is an enzyme that hydrolyzes some bacterial cell-walls, the bacterium used for the assay being Micrococcus lysodeikticus. Lysozyme is found in a wide variety of species and locations, including bacteriophages, blood, egg white, gastric secretions, milk, nasal mucus, papaya, sputum, and tears. The outstanding achievement in this field has been the elucidation of the crystal structures of some of the lysozyme-substrate complexes. 

In this laboratory we have examined the ORD of various membrane systems including heavy beef heart submitochondrial vesicles, rat liver submitochondrial vesicles, erythrocyte ghosts, and the membranes of Micrococcus lysodeikticus, Halobacterium halobium, Halobacterium cuti-rubrum, and Mycoplasma laidlawii. The optical behavior of all these materials is strikingly similar the Cotton effects are similar to those produced by an a-helix but are red shifted to abnormally high wavelengths (71). Cotton effects arising from amide transitions in other... 

In 1964, Tsuda and Strauss discovered a DNase activity in crude extracts of Micrococcus lysodeikticus (later renamed Micrococcus luteus) which required a nucleoside di- or triphosphate for activity (48). This enzyme has recently been purified extensively (2400-fold) and examined in detail by Takagi and his colleagues (49). It has an alkaline pH... 

J. Friedberg and G. Avigad (1968). Structures containing polyphosphate in Micrococcus lysodeikticus. J. Bacteriol., 96, 544-553. 

Protein Production, Isolation, and Purification. The expression and purification of chicken lysozyme mutant proteins in yeast are performed as described by Malcolm et al. with the following modifications. The 50-ml minimal medium second seed yeast culture is used to inoculate a 2.8-liter Fembach flask containing 500 ml of 1% yeast extract/2% Bacto-peptone/ 8% glucose (w/v) medium and is then incubated for 7 - 9 days at 30°. Cells are harvested, washed twice with 60 ml of 0.5 M NaCl, and collected by centrifugation. The supernatants are pooled, diluted 5-fold with deionized water, and loaded onto a 20-ml column of CM Sepharose Fast Flow (Pharmacia, Piscataway, NJ) equilibrated with 0.1 M potassium phosphate, pH 6.24. The column is washed with the same buffer, and lysozyme is eluted with 0.5 M NaCl/0.1 M potassium phosphate, pH 6.24. Fractions are assayed by activity (decrease in A450 of Micrococcus lysodeikticus cell wall suspensions per minute). Fractions containing lysozyme are concentrated in Centricon-10 (Amicon, Danvers, MA) filter units, washed with 0.1 M potassium phosphate buffer, pH 6.24, and stored at 4°. The protein concentration is determined from e 1 = 26.4.15... 

Competitive Inhibition Enzyme Assays. Estimates of antibody-lysozyme dissociation constants can be obtained by taking advantage of the fact that most monoclonal antibodies efficiently inhibit enzymatic activity.3 5 The combining site of HyHEL-10, which is presented as an example, also has been demonstrated by X-ray crystallography to overlap a portion of the catalytic site of lysozyme.7 A constant concentration of lysozyme is incubated with varying amounts of antibody, and amounts of free (unbound) lysozyme molecules are estimated by the proportion of catalytic activity remaining. The assay assumes that the addition of Micrococcus lysodeikticus cell walls and concurrent dilution of the antibody-antigen mixture do not disturb the equilibrium. 

Activity is measured by the procedure of Shugar.21 To 2.9-ml cuvettes (1 cm path length), diluted lysozyme (ranging from 0.1 to 0.5 nM) and antibody (ranging from 0.013 to 50 nM) are added to 66 mM potassium phosphate buffer, pH 6.24, and 0.1% bovine serum albumin (BSA) (w/v) to a volume of 900 fil. The solutions are kept at 25° for 1 hr to allow the lysozyme-antibody complexes to come to equilibrium. The activity assays are initiated by the addition of 100 pi Micrococcus lysodeikticus (Sigma Chemical Company) cell walls (2 mg/ml in 66 mM potassium phosphate, pH 6.24) to a final A450 of 0.8 -1.0. Cuvettes are wrapped with Parafilm to prevent evaporation, inverted several times to mix, and placed in a Perkin-Elmer, Norwalk, CT) Lambda 4B spectrophotometer. Reactions are monitored by the decrease in A450 for 70 min with a data point collected every minute. 

Catalase (Micrococcus lysodeikticus) Produced by controlled fermentation using Micrococcus lysodeikticus. Soluble in water (the solution is usually light yellow to dark brown), but practically insoluble in alcohol, in chloroform, and in ether. Major active principle catalase. Typical application used in the manufacture of cheese, egg products, and soft drinks. 

Catalase oxidoreductase (1) Aspergillus niger var. (2) bovine liver (3) Micrococcus lysodeikticus hydrogen peroxide hydrogen peroxide oxidoreductase 1.11.1.6... 

Application and Principle This procedure is used to determine the catalase activity, expressed as Baker Units, of preparations derived from Aspergillus niger var., bovine liver, or Micrococcus lysodeikticus. The assay is an exhaustion method based on the breakdown of hydrogen peroxide by catalase and the simultaneous breakdown of the catalase by the peroxide under controlled conditions. 

Application and Principle The purpose of this procedure is to determine the lysozyme activity in purified lysozyme preparations derived from animal or microbial sources. The assay is based on the rate of decrease in absorbance at 450 nm, attributed to the lysis of Micrococcus lysodeikticus by lysozyme. The decrease in absorbance is measured using a UV/V spectrophotometer equipped to control the sample temperature at 25°. 

Calculation One lysozyme unit is defined as the amount of lysozyme that causes a decrease in absorbance of 0.001 per min at 450 nm, 25°, and pH 6.2, using a suspension of Micrococcus lysodeikticus as the substrate. 

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