scholarly journals Sedimentation Equilibrium Studies on Protein From Kookaburra Beak

1976 ◽  
Vol 29 (6) ◽  
pp. 481
Author(s):  
EF Woods
Keyword(s):  
Molecular Weight ◽  
Optical System ◽  
Optical Rotatory Dispersion ◽  
Rotatory Dispersion ◽  
Sedimentation Equilibrium ◽  
Optical Rotatory ◽  
Equilibrium Studies ◽  
Aqueous Buffer ◽  
Random Coils ◽  
Equilibrium Sedimentation

Fractionated samples of the soluble S-carboxymethyl proteins from kookaburra beak (Frenkel and Gillespie 1976) were examined by equilibrium sedimentation. The molecular weight was found to be 11 300 when the photoelectric scanning absorption optical system was employed and 13 700 when Rayleigh interference optics were used. Possible explanations for this difference are considered and it is concluded that it must arise from heterogeneity of the protein. Optical rotatory dispersion measurements indicate that the proteins probably exist as random coils in dilute aqueous buffer.

scholarly journals Purification and properties of 6-phosphogluconate dehydrogenase from sheep liver

1969 ◽  
Vol 115 (4) ◽  
pp. 639-643 ◽  
Author(s):  
R. H. Villet ◽  
K. Dalziel
Keyword(s):  
Molecular Weight ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sedimentation Velocity ◽  
Sedimentation Equilibrium ◽  
Equilibrium Studies ◽  
Phosphogluconate Dehydrogenase ◽  
Sheep Liver ◽  
Equilibrium Sedimentation ◽  
Purification And Properties

A method is described for the isolation of 6-phosphogluconate dehydrogenase from sheep liver. The product appears to be homogeneous in polyacrylamide-gel electrophoresis and in sedimentation-velocity and sedimentation-equilibrium studies in the ultracentrifuge. The molecular weight is estimated as 129000 from equilibrium sedimentation.

Physicochemical Studies of Conglutin γ, a Storage Globulin From Seeds of Lupinus angustifolius

1980 ◽  
Vol 7 (1) ◽  
pp. 1 ◽  
Author(s):  
RJ Blagrove ◽  
JM Gillespie ◽  
GG Lilley ◽  
EF Woods
Keyword(s):  
Molecular Weight ◽  
Guanidine Hydrochloride ◽  
Polyacrylamide Gel Electrophoresis ◽  
Polyacrylamide Gel ◽  
Optical Rotatory Dispersion ◽  
Sedimentation Equilibrium ◽  
Native Protein ◽  
Equilibrium Studies ◽  
Physicochemical Studies ◽  
Α Helix

Physicochemical studies are reported for conglutin �, the minor globulin isolated from seeds of L. angustifolius cv. Uniwhite. Isoelectric focusing of the native protein in polyacrylamide gel slabs resolved major and minor broad bands near pH 8.0 and 7.8 respectively. Following reduction of disulfide bonds with β-mercaptoethanol in 8 M urea, the smaller polypeptide chain of known sequence focused near pH 6.9 while the larger chain focused near pH 8.0. Sedimentation equilibrium studies showed that the major component in aqueous buffers at neutral pH is a hexamer of molecular weight 280 000 which dissociates to the monomer of molecular weight 47 000 at pH 4.8. The sequence molecular weight of the small subunit polypeptide is 16 517 [Elleman, T.C. (1977). Aust. J. Biol. Sci. 30, 33-45]. The molecular weights determined for the larger chain by sedimentation equilibrium or column chromatography in 6 M guanidine hydrochloride, and by dodecyl sulfate-polyacrylamide gel electrophoresis, were in the range 28 000-30 000. Optical rotatory dispersion and circular dichroism measurements have been used to establish the approximate proportions of α-helix (15%), β-structure (35%), β-turns (18%) and unordered regions (32%) in the native protein. The denaturation curve for guanidine hydrochloride and the proportions of α-helix (50%), β-turns (18%) and unordered regions (32%) in 80 % trifluoroethanol have been determined.

Physicochemical studies on the aggregation of bovine cardiac tropomyosin with ionic strength

1969 ◽  
Vol 47 (4) ◽  
pp. 411-413 ◽  
Author(s):  
William D. McCubbin ◽  
Cyril M. Kay
Keyword(s):  
Ionic Strength ◽  
High Ionic Strength ◽  
Optical Rotatory Dispersion ◽  
Rotatory Dispersion ◽  
Sedimentation Equilibrium ◽  
Velocity Sedimentation ◽  
Optical Rotatory ◽  
Dispersion Parameters ◽  
Tertiary Structures ◽  
The Individual

The aggregation of bovine cardiac tropomyosin as a function of ionic strength has been studied by the techniques of sedimentation velocity, sedimentation equilibrium, osmometry, viscometry, and optical rotatory dispersion. The measurements indicate that in aqueous buffers at neutral pH and at ionic strengths below 0.6, cardiac tropomyosin is heterogeneous and consists of a monomer in equilibrium with its aggregates. Dissociation of the aggregates occurs on dilution to yield a molecular weight species of approximately 70 000, in very good agreement with the value obtained at high ionic strength. These observations essentially parallel similar findings noted for the polymerization of skeletal tropomyosin, with the exception that the cardiac protein shows no tendency to polymerize at high ionic strength. The virtual constancy of all the optical rotatory dispersion parameters with polymerization suggests that the association is probably linear rather than lateral, with no accompanying changes in secondary and tertiary structures of the individual monomers.

Proteins as random coils. III. Optical rotatory dispersion in 6M guanidine hydrochloride

1967 ◽  
Vol 89 (19) ◽  
pp. 5023-5029 ◽  
Author(s):  
Charles. Tanford ◽  
Kazuo. Kawahara ◽  
Savo. Lapanje ◽  
Thomas M. Hooker ◽  
Mario H. Zarlengo ◽  
...  
Keyword(s):  
Guanidine Hydrochloride ◽  
Optical Rotatory Dispersion ◽  
Rotatory Dispersion ◽  
Optical Rotatory ◽  
Random Coils

The conformation of an atypical IgG myeloma protein and its papain fragments

1970 ◽  
Vol 48 (7) ◽  
pp. 784-789 ◽  
Author(s):  
G. E. Connell ◽  
K. J. Dorrington ◽  
A. F. Lewis ◽  
D. M. Parr
Keyword(s):  
Molecular Weight ◽  
The Other ◽  
Optical Rotatory Dispersion ◽  
Rotatory Dispersion ◽  
Optical Rotatory ◽  
Fab Fragment ◽  
Myeloma Protein ◽  
Myeloma Proteins ◽  
Parent Protein ◽  
Polypeptide Chains

An immunoglobulin IgG (Sackfield) which is known to have polypeptide chains shorter than those of typical proteins of its class has been subjected to fragmentation by papain in the presence of cysteine. One fragment was recovered which was indistinguishable from normal Fc fragment. The other fragment was related to normal Fab fragment but differed from it in several of its properties. The molecular weight was only one-half that of normal Fab. The optical rotatory dispersion spectrum of IgG (Sackfield) had features which differed from those of typical IgG myeloma proteins. The optical rotatory dispersion spectrum of Fc (Sackfield) was identical with those of other myeloma proteins, while the Fab (Sackfield) spectrum reflected the differences observed in the parent protein.

scholarly journals Molecular weight of Escherichia coli β-galactosidase in concentrated solutions of guanidine hydrochloride

1970 ◽  
Vol 120 (2) ◽  
pp. 255-261 ◽  
Author(s):  
Robert P. Erickson
Keyword(s):  
Escherichia Coli ◽  
Molecular Weight ◽  
Guanidine Hydrochloride ◽  
Average Molecular Weight ◽  
Sedimentation Velocity ◽  
Sedimentation Equilibrium ◽  
Weight Average Molecular Weight ◽  
Random Coils ◽  
Equilibrium Sedimentation ◽  
Apparent Weight

The molecular weight of Escherichia coli β-galactosidase was determined in 6m- and 8m-guanidine hydrochloride by meniscus-depletion sedimentation equilibrium, sedimentation velocity and viscosity. Sedimentation equilibrium revealed heterogeneity with the smallest component having a molecular weight of about 50000. At lower speeds, the apparent weight-average molecular weight is about 80000. By use of a calculation based on an empirical correlation for proteins that are random coils in 6m-guanidine hydrochloride, sedimentation velocity gave a molecular weight of 91000, and the intrinsic viscosity indicated a viscosity-average molecular weight of 84000. Heating in 6m-guanidine hydrochloride lowered the viscosity of β-galactosidase in a variable manner.

scholarly journals Sedimentation-equilibrium and other physicochemical studies on the lysine-rich fraction of calf thymus histones

1968 ◽  
Vol 110 (2) ◽  
pp. 243-250 ◽  
Author(s):  
A. J. Haydon ◽  
A. R. Peacocke
Keyword(s):  
Molecular Weight ◽  
Virial Coefficient ◽  
Average Molecular Weight ◽  
Second Virial Coefficient ◽  
Apparent Molecular Weight ◽  
Optical Rotatory Dispersion ◽  
Sedimentation Equilibrium ◽  
Acid Extraction ◽  
Equilibrium Studies ◽  
Calf Thymus

1. The lysine-rich fraction (Ia+Ib, or f1) of calf thymus histones was isolated as the sulphate by acid extraction. 2. Sedimentation-equilibrium measurements with interference optics showed that this fraction was monodisperse with a molecular weight of 19500±2000. 3. The ‘apparent molecular weight’ calculated from the sedimentation-equilibrium studies varied markedly with concentration. The large second virial coefficient implied by such variation was attributed to the very high charge/mass ratio of this relatively small protein. Estimates of the charge were made from the values of this virial coefficient. 4. The very large value of the virial coefficient explains anomalies in the earlier reports of the molecular weight of this histone and also why the z-average molecular weight can appear to be lower than the weight-average molecular weight. 5. The differences of the specific refractive increments, and the partial specific volumes, between dialysed and undialysed solutions of this histone fraction could also be attributed to its high molecular charge, which was estimated from these differences and agreed, within the expected limits, with the value deduced from the second virial coefficient. 6. Sedimentation-velocity measurements combined with the known molecular weight imply that lysine-rich histone has a high frictional ratio and an extended shape. Optical-rotatory-dispersion measurements indicated that it had a low helical content.

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