scholarly journals THE PROTEINS IN UNHEATED CULTURE FILTRATES OF HUMAN TUBERCLE BACILLI

1948 ◽  
Vol 87 (3) ◽  
pp. 229-244 ◽  
Author(s):  
Ellen B. Bevilacqua ◽  
Janet R. McCarter
Keyword(s):  
Molecular Weight ◽  
Diffusion Rate ◽  
Sedimentation Velocity ◽  
Partial Specific Volume ◽  
Velocity Measurements ◽  
Physical Measurements ◽  
Sedimentation Constant ◽  
Diffusion Constants ◽  
Culture Filtrates ◽  
And Diffusion

Concentrated culture filtrates of two strains of human tubercle bacilli, a virulent and a slightly virulent one, have been fractionated to give fourteen fractions in each case. Chemical determinations and sedimentation velocity measurements have been carried out on those fractions for which significant results could be obtained. The evidence is that two distinct proteins are present, in addition to a polysaccharide and nucleic acid. The physical measurements have not demonstrated the presence of any other proteins. One of the proteins has been isolated in pure form, and found to have a molecular weight of 44,000 ± 5,000, based on measurements of partial specific volume, sedimentation velocity, and diffusion rate. This protein is believed to be the same as one previously isolated by Seibert et al. (6), who assigned it a molecular weight of 32,000. The other protein was not obtained sufficiently free from polysaccharide so that its molecular weight could be determined, but it is believed to have a sedimentation constant of about 2 S. Sedimentation and diffusion constants have been obtained for the polysaccharide, which appears to be a homogeneous molecular species with a molecular weight of about 20,000. The source in unheated tuberculin of the proteins obtained from heated preparations is discussed.

scholarly journals THE MOLECULAR WEIGHT AND ISOELECTRIC POINT OF THYROGLOBULIN

1935 ◽  
Vol 19 (1) ◽  
pp. 95-108 ◽  
Author(s):  
Michael Heidelberger ◽  
Kai O. Pedersen
Keyword(s):  
Molecular Weight ◽  
Isoelectric Point ◽  
Specific Volume ◽  
Sedimentation Equilibrium ◽  
Sedimentation Constant ◽  
Diffusion Constants ◽  
Equilibrium Data ◽  
Round Numbers ◽  
And Diffusion

1. The sedimentation constant of hog thyroglobulin is 19.2ċ10–13. That of human thyroglobulin is essentially the same. 2. The specific volume of hog thyroglobulin is 0.72. 3. The isoelectric point of native hog thyroglobulin is at pH 4.58, that of denatured thyroglobulin at pH 5.0. 4. The molecular weight of hog thyroglobulin is, in round numbers, 700,000, as calculated from the sedimentation and diffusion constants, or 650,000, as calculated from the sedimentation equilibrium data. 5. The thyroglobulin molecule deviates markedly from the spherical.

Das Molekulargewicht der Peptideinheit im Protein des Tabakmosaikvirus

1959 ◽  
Vol 14 (1) ◽  
pp. 24-28 ◽  
Author(s):  
F. Alfred Anderer
Keyword(s):  
Molecular Weight ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Alkaline Solution ◽  
Diffusion Constants ◽  
And Diffusion

The protein of tobacco mosaic virus was extracted by phenol. After precipitation with methanol the sedimentation and diffusion constants were measured in alkaline solution. At pH 13,0 S20=2.0 and D20=9.6 was found. From these data a molecular weight of 18 800 ± 10% can be calculated, which corresponds to the size of the peptide subunit found by the endgroup determination.

STUDIES ON ϵ-PROTOTOXIN OF CLOSTRIDIUM PERFRINGENS TYPE D

1964 ◽  
Vol 42 (4) ◽  
pp. 545-554 ◽  
Author(s):  
A. F. S. A. Habeeb
Keyword(s):  
Clostridium Perfringens ◽  
Moving Boundary ◽  
Deae Cellulose ◽  
Paper Electrophoresis ◽  
Disc Electrophoresis ◽  
Type D ◽  
Sedimentation Constant ◽  
Diffusion Constants ◽  
Starch Gel ◽  
And Diffusion

Purified prototoxin of Clostridium perfringens type D was separated by column chromatography on CM-cellulose or DEAE-cellulose into two and three fractions respectively. The fractions exhibited prototoxin activity and showed immunochemical identity. The purified prototoxin gave a single component in the ultracentrifuge with a sedimentation constant of 2.85 S. The molecular weight was 25,100 ± 1500 and 23,200 when determined by the Archibald method and from sedimentation and diffusion constants respectively. Although the prototoxin was homogeneous by paper electrophoresis and moving boundary electrophoresis at pH 4.5, its heterogeneity was demonstrated on moving boundary electrophoresis at pH 8.6; 72% of material had a mobility of −1 × 10−5 cm2/v sec and 28% with a mobility of −2.7 × 10−5 cm2/v sec. The electrophoretic heterogeneity was also demonstrated on starch gel and disc electrophoresis. Amino acid analysis showed the presence of hydroxyproline and four uncommon amino acids; two of the latter were identified tentatively as hydroxylysine and allohydroxylysine.

scholarly journals THE LS-ANTIGEN OF VACCINIA

1943 ◽  
Vol 77 (2) ◽  
pp. 155-164 ◽  
Author(s):  
Theodore Shedlovsky ◽  
Alexandre Rothen ◽  
Joseph E. Smadel
Keyword(s):  
Molecular Weight ◽  
Isoelectric Point ◽  
Specific Volume ◽  
Degradation Products ◽  
Diffusion Constant ◽  
Partial Specific Volume ◽  
Analytical Ultracentrifuge ◽  
Axis Ratio ◽  
Ellipsoidal Shape ◽  
Sedimentation Constant

Studies on LS-protein, the soluble double antigen of vaccinia, and on the degradation products L'S and L''S' have been made with electrophoresis and in the analytical ultracentrifuge. LS, which is homogeneous electrically and in the ultracentrifuge, has an isoelectric point at pH 4.8. At 4°C. its partial specific volume is 0.72 cc./gm., and its diffusion constant is 1.50 x 10–7 cm.2/sec. The sedimentation constant is 6.35 at 20°C., the molecular weight is 214,000, and the molecule appears to have an elongated ellipsoidal shape with an axis ratio of 1:20. L'S and L''S' are homogeneous electrically but not in the ultracentrifuge, L''S' being extremely polydisperse.

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.

ULTRACENTRIFUGE AND DIFFUSION STUDIES ON GLUTEN

1942 ◽  
Vol 20c (3) ◽  
pp. 130-159 ◽  
Author(s):  
A. G. McCalla ◽  
Nils Gralén
Keyword(s):  
Sodium Salicylate ◽  
Minimum Weight ◽  
Average Molecular Weight ◽  
Sedimentation Equilibrium ◽  
Velocity Sedimentation ◽  
Molecular Characteristics ◽  
Weight Average Molecular Weight ◽  
Diffusion Constants ◽  
Diffusion Studies ◽  
And Diffusion

The molecular characteristics of gluten in sodium salicylate solutions were studied by means of sedimentation velocity, sedimentation equilibrium, and diffusion measurements. The proportion of total gluten protein molecularly dispersed increased with increase in concentration of sodium salicylate up to 12%, but the dispersed portions had essentially the same sedimentation constant (2.5 ± 0.15) regardless of the concentration of the dispersing medium.The most soluble 25 per cent of the gluten was all molecularly dispersed, but was definitely inhomogeneous. The weight-average molecular weight of this fraction was 44,000, but there is reason to believe the minimum weight may be about 35,000. None of the other fractions was entirely molecularly dispersed, the proportion decreasing with decreasing solubility of the fractions. Aggregates of many sizes existed in all of these fractions, but only the most insoluble contained aggregates large enough to cause opacity. Sedimentation constants of the molecularly dispersed portions increased slightly with decreasing solubility, while diffusion constants decreased markedly. None of the fractions yielded normal curves (diffusion diagrams) but the more soluble the fraction, the more nearly normal the curve. The inhomogeneity responsible for the varying rates of diffusion was due partly to differences in proportion and properties of the molecularly dispersed gluten and partly to aggregates.All properties showed progressive changes both within and between the arbitrarily produced fractions. These results, therefore, support the hypothesis that gluten is a protein system showing progressive and regular changes in properties with change in solubility.

scholarly journals MOLECULAR WEIGHT AND ELECTROPHORESIS OF CRYSTALLINE RIBONUCLEASE

1940 ◽  
Vol 24 (2) ◽  
pp. 203-211 ◽  
Author(s):  
Alexandre Rothen
Keyword(s):  
Molecular Weight ◽  
Isoelectric Point ◽  
Unit Weight ◽  
Diffusion Measurement ◽  
Average Value ◽  
Rate Of Sedimentation ◽  
And Diffusion ◽  
Good Agreement

Electrophoretic studies on purified crystalline ribonuclease showed the absence of any impurities differing in mobility from the bulk of material. The isoelectric point of ribonuclease was found by electrophoresis to be at about pH 7.8. Ultracentrifuge studies indicated fair homogeneity of ribonuclease in solution. Only one moving component has been observed. The molecular weight of ribonuclease was found to be 12,700 from rate of sedimentation (S25 = 1.85 x 10–13 in 0.5 M (NH4)2SO4) and diffusion measurement (D = 1.36 x 10–6 in 0.5 M (NH4)2SO4), in good agreement with the average value of 13,000 found from equilibrium measurements. This low value for the molecular weight of a protein would seem to discredit the value 17,600 as representing a universal unit weight for proteins in general.

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