EFFECT OF PROPYLTHIOURACIL ON THE IODINATION AND MATURATION OF RAT THYROGLOBULIN

1966 ◽  
Vol 53 (2) ◽  
pp. 271-285 ◽  
Author(s):  
Claude Simon ◽  
Marie Roques ◽  
Janine Torresani ◽  
Serge Lissitzky
Keyword(s):  
Single Injection ◽  
Freezing And Thawing ◽  
Isotopic Equilibrium ◽  
Sedimentation Constant

ABSTRACT The effect of propylthiouracil on the maturation of rat thyroglobulin in vivo has been investigated. Newly iodinated thyroglobulin dimer is labile to freezing and thawing. This observation has been used to interpret the findings in the present experiments. From experiments using rats in isotopic equilibrium with 125I, and treated with propylthiouracil or propylthiouracil and tri-iodothyronine and also given a single injection of 131I, the following conclusions were formulated 1) the appearance of iodinated S12 thyroglobulin monomer is due to the dissociation of labile iodinated thyroglobulin dimer and appears more readily if the dimer is poorly iodinated, 2) uniodinated thyroglobulin dimer is the most probable substrate for iodination in vivo, 3) maturation of thyroglobulin dimer (as shown by increasing sedimentation constant from 16—17 to 19) is accompanied by increasing amounts of iodine in the molecule, 4) it is not possible to say at present if iodination and iodothyronine formation is the cause or the consequence of thyroglobulin dimer maturation, 5) propylthiouracil might inhibit thyroglobulin maturation by decreasing iodine organification.

scholarly journals CONCENTRATION AND PURIFICATION OF BACTERIOPHAGE

1938 ◽  
Vol 21 (3) ◽  
pp. 335-366 ◽  
Author(s):  
John H. Northrop
Keyword(s):  
Molecular Weight ◽  
Small Molecules ◽  
Specific Activity ◽  
Active Agent ◽  
Pure Substance ◽  
Solubility Curve ◽  
Denatured Protein ◽  
Sedimentation Constant ◽  
Rate Of Sedimentation ◽  
Living Organisms

1. A method for isolating a nucleoprotein from lysed staphylococci culture is described. 2. It is homogeneous in the ultracentrifuge and has a sedimentation constant of 650 x 10–13 cm. dyne–1 sec.–1, corresponding to a molecular weight of about 300,000,000. 3. The diffusion coefficient varies from about 0.001 cm.2/day in solutions containing more than 0.1 mg. protein/ml. to 0.02 in solutions containing less than 0.001 mg. protein/ml. The rate of sedimentation also decreases as the concentration decreases. It is suggested, therefore, that this protein exists in various sized molecules of from 500,000–300,000,000 molecular weight, the proportion of small molecules increasing as the concentration decreases. 4. This protein is very unstable and is denatured by acidity greater than pH 5.0, by temperature over 50°C. for 5 minutes. It is digested by chymo-trypsin but not by trypsin. 5. The loss in activity by heat, acid, and chymo-trypsin digestion is roughly proportional to the amount of denatured protein formed under these conditions. 6. The rate of diffusion of the protein is the same as that of the active agent. 7. The rate of sedimentation of the protein is the same as that of the active agent. 8. The loss in activity when susceptible living or dead bacteria are added to a solution of the protein is proportional to the loss in protein from the solution. Non-susceptible bacteria remove neither protein nor activity. 9. The relative ultraviolet light absorption, as determined directly, agrees with that calculated from Gates' inactivation experiments in the range of 2500–3000 Å. u. but is somewhat greater in the range of 2000–2500 Å. u. 10. Solubility determinations showed that most of the preparations contained at least two proteins, one being probably the denatured form of the other. Two preparations were obtained, however, which had about twice the specific activity of the earlier ones and which gave a solubility curve approximating that of a pure substance. 11. It is suggested that the formation of phage may be more simply explained by analogy with the autocatalytic formation of pepsin and trypsin than by analogy with the far more complicated system of living organisms.

scholarly journals THE PREPARATION AND PROPERTIES OF BACTERIAL CHROMATOPHORE FRACTIONS

1964 ◽  
Vol 23 (1) ◽  
pp. 135-150 ◽  
Author(s):  
Patricia Barron Worden ◽  
W. R. Sistrom
Keyword(s):  
Growth Conditions ◽  
Heavy Fraction ◽  
Light Fraction ◽  
Pigment Content ◽  
Photosynthetic Unit ◽  
Whole Cells ◽  
Sedimentation Constant ◽  
Infra Red ◽  
Rhodopseudomonas Spheroides ◽  
Qualitative Changes

Chromatophore material from the bacterium Rhodopseudomonas spheroides was freed of ribosomes by centrifugation in 27 per cent RbCl and then separated into "heavy" and "light" fractions by centrifugation through a sucrose gradient. The fractions differed from one another in the following ways. (a) The isopycnic density of the heavy fraction was between 1.15 and 1.18 gm/ml and that of the light fraction was 1.14 gm/ml. (b) The heavy fraction was able to bind ribosomes; the light fraction was not. (c) The light fraction was homogeneous in the ultracentrifuge and had a sedimentation constant, extrapolated to infinite dilution, of 153 s20,w. The heavy fraction was grossly heterogeneous. (d) Both the amount of bacteriochlorophyll relative to protein and the ratio of bacteriochlorophyll to carotenoids were greater in the light fraction. (e) The spectra of the two fractions in the near infra-red were different. Comparisons of the chromatophore fractions from cells with different amounts of bacteriochlorophyll showed that the specific bacteriochlorophyll contents of the two fractions did not change to the same extent as did that of the whole cells. The amount of heavy fraction from pigmented cells was roughly independent of the cellular pigment content and was about equal to that from pigment-free cells. The amount of light fraction depended on the pigment content of the cells; no light fraction was obtained from cells devoid of bacteriochlorophyll. The cytochrome complements of both fractions underwent quantitative as well as qualitative changes with varying growth conditions. The size of the photosynthetic unit in R. spheroides appeared to increase as the total cellular bacteriochlorophyll content increased; however, the number of units per light fraction particle remained constant.

scholarly journals TWO PROTEINS PURIFIED FROM LOBSTER NERVE EXTRACT

1955 ◽  
Vol 1 (4) ◽  
pp. 279-286 ◽  
Author(s):  
Myles Maxfield ◽  
Robert W. Hartley
Keyword(s):  
Zinc Acetate ◽  
Protein Component ◽  
Sedimentation Constant ◽  
Physicochemical Data

1. A protein component, fraction B, of lobster nerve extracts has been isolated and purified by differential ultracentrifugation and precipitation with zinc acetate. 2. Physicochemical data obtained from this protein and from fraction C are summarized. 3. Fraction B is present in lobster nerve extracts in higher concentration (relative to fraction A) than in blood. 4. A second component, fraction C, of sedimentation constant S20o = 13.2 has been isolated from lobster nerve extracts.

FURTHER STUDIES ON THE PURIFICATION OF THROMBIN

1958 ◽  
Vol 36 (1) ◽  
pp. 603-611 ◽  
Author(s):  
Walter H. Seegers ◽  
Walter G. Levine ◽  
Robert S. Shepard
Keyword(s):  
Molecular Weight ◽  
Phosphate Buffer ◽  
Esterase Activity ◽  
Room Temperature ◽  
Specific Activity ◽  
Dry Weight ◽  
The Other ◽  
Resin Column ◽  
Sedimentation Constant ◽  
Single Symmetrical Peak

Purified biothrombin (bovine) was fractionated with the use of amberlite IRC-50 columns to obtain resin thrombin with an activity of 4100 units/mg. dry weight or 45,000 units/mg. tyrosine. As obtained from a resin column in 0.3 M phosphate buffer, pH 8.0, the thrombin is stable for 5 days at room temperature. At 4 °C. about 70% of the activity remains after 20 weeks. The maximum molecular weight is estimated by comparing with the specific activity (2000 units/mg.) and molecular weight (62,700) of purified prothrombin as follows: 2000/4100 × 62,700 or 30,600 as the probable molecular weight. Resin thrombin can lose its fibrinogen-clotting power while esterase activity is retained. On the other hand the esterase activity can be depressed without diminishing the clotting activity. Resin thrombin lyses fibrin. When examined in an ultracentrifuge a single symmetrical peak was found with a sedimentation constant of S = 3.9 (20 °C., 0.1 M KCl, 5.5 mg./ml.) Citrate thrombin was also fractionated with the use of IRC-50 to obtain material with a specific activity of 47,000 units/mg. tyrosine.

scholarly journals THE PREPARATION AND PHYSICOCHEMICAL CHARACTERIZATION OF THE SERUM PROTEIN COMPONENTS OF COMPLEMENT

1941 ◽  
Vol 74 (4) ◽  
pp. 297-308 ◽  
Author(s):  
L. Pillemer ◽  
E. E. Ecker ◽  
J. L. Oncley ◽  
E. J. Cohn
Keyword(s):  
Ionic Strength ◽  
Guinea Pig ◽  
Potassium Chloride ◽  
Electrophoretic Mobility ◽  
Phosphate Buffer ◽  
Physicochemical Characterization ◽  
Sedimentation Constant ◽  
Protein Components ◽  
Pig Serum

1. Methods for the separation from guinea pig serum in highly purified form of three of the components of complement are described. These substances are the so called mid-piece, end-piece, and 4th component. 2. Mid-piece has been separated as a euglobulin, with an electrophoretic mobility of 2.9 x 10–5 in phosphate buffer of ionic strength 0.2 at pH 7.7, and with a sedimentation constant of 6.4 x 10–13 in potassium chloride of ionic strength 0.2. 3. End-piece and 4th component were found together in a euglobulin fraction of serum which contained 10.3 per cent carbohydrate and had an electrophoretic mobility of 4.2 x 10–5 in phosphate buffer of ionic strength 0.2 at pH 7.7.

Ultracentrifugal studies of the infective and complement-fixing components in the virus system of foot-and-mouth disease

1952 ◽  
Vol 140 (898) ◽  
pp. 107-127 ◽  
Keyword(s):  
High Speed ◽  
Active Component ◽  
Foot And Mouth Disease ◽  
Mouth Disease ◽  
Biologically Active ◽  
Sedimentation Constant ◽  
Foot And Mouth ◽  
Initial Infectivity ◽  
Virus System

The sedimentation constant of the infective particle in foot-and-mouth disease has been determined by modifications of the methods of Elford (1936) and Polsen (1941). A new high-speed, swinging-cup rotor was employed. A sedimentation constant of 70 Svedberg units was obtained for the infective particle in a variety of starting materials derived from guineapigs, mice and cattle. The validity of the data is discussed in relation to the accuracy with which a sedimentation constant may be determined by these methods. Ultracentrifugal studies employing inclined tubes have demonstrated that in fresh preparations the infective particle is associated with from 0 to 50% of the initial complement-fixing activity. The remaining complement-fixing activity is associated with a component of sedimentation constant 8 Svedberg units. This slower sedimenting component, if infective, contributes less than 0⋅01% of the initial infectivity. A direct and relatively precise method is described for the determination of the partition of a biological activity between two or more components of a virus system. By the use of radial and inclined tubes in non-optical procedures a correlation between these methods has been established. It is shown that the sedimentation constant of a biologically active component may be estimated by procedures based on sampling in inclined tubes. The G integral is introduced as an accurate and convenient parameter which greatly facilitates the calculation and presentation of the results of ultracentrifugal studies.

scholarly journals THE SIZE OF INFLUENZA VIRUS

1944 ◽  
Vol 79 (3) ◽  
pp. 267-283 ◽  
Author(s):  
W. M. Stanley
Keyword(s):  
Molecular Weight ◽  
Influenza Virus ◽  
High Molecular Weight ◽  
Particle Diameter ◽  
Allantoic Fluid ◽  
Sucrose Density Gradient ◽  
Chick Embryos ◽  
Sedimentation Behavior ◽  
Virus Activity ◽  
Sedimentation Constant

The sedimentation behavior of influenza virus in dilute solutions of electrolyte was found to be quite variable. At times the virus activity appeared to sediment at a rate comparable with that of particles about 80 to 120 mµ in diameter, at other times at a rate comparable with that of particles about 10 mµ in diameter, and at still other times the bulk of the activity appeared to sediment at a rate comparable with that of the larger particles and the residual activity at a rate comparable with that of the smaller particles. However, in the presence of a sucrose density gradient, the virus activity was always found to sediment with a rate comparable to that of particles about 80 to 120 mµ in diameter; hence it appeared that the variable sedimentation behavior in dilute electrolyte solution was due to convection or mechanical disturbances during centrifugation. About 30 per cent of the high molecular weight protein present in the allantoic fluid of chick embryos infected with the F 12 strain of influenza virus was found to consist of a component having a sedimentation constant of about 30 S, and hence a probable particle diameter of about 10 mµ. The residual protein of high molecular weight was present in the form of a component having a sedimentation constant of about 600 S, and hence a probable particle diameter of about 70 mµ. The proportion of the 30 S component in allantoic fluid of chick embryos infected with the PR8 strain of influenza virus was found to be considerably less. The 600 S and 30 S components of F 12 allantoic fluid were purified and separated by differential centrifugation. The purified preparations of the 600 S component were found to possess a specific virus activity from 100 to over 10,000 times that of the purified preparations of the 30 S component, the difference in activity apparently depending only on the degree of fractionation of the two components. The purified 30 S component was found to sediment normally in the presence of 12 per cent sucrose, whereas the small residual virus activity of such preparations was found to sediment in the presence of a sucrose density gradient with a rate comparable to that of much heavier particles. It is concluded that influenza virus activity is not associated with material having a particle diameter of about 10 mµ, but is associated solely with material having a sedimentation constant of about 600 S and hence a probable particle diameter of about 70 mµ.

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