Evidence for Conformational Changes in α-Chymotrypsin-catalyzed Reactions. VI. Changes in Optical Rotatory Dispersion Parameters

1963 ◽  
Vol 85 (6) ◽  
pp. 791-796 ◽  
Author(s):  
Bent H. Havsteen ◽  
George P. Hess
Keyword(s):  
Conformational Changes ◽  
Optical Rotatory Dispersion ◽  
Rotatory Dispersion ◽  
Optical Rotatory ◽  
Dispersion Parameters ◽  
Catalyzed Reactions

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.

scholarly journals Studies of the denaturation and partial renaturation of ovalbumin

1972 ◽  
Vol 129 (3) ◽  
pp. 665-676 ◽  
Author(s):  
J. C. Holt ◽  
J. M. Creeth
Keyword(s):  
Sodium Dodecyl Sulphate ◽  
Sodium Dodecyl ◽  
Sedimentation Coefficient ◽  
Optical Rotatory Dispersion ◽  
Rotatory Dispersion ◽  
Physical Parameters ◽  
Optical Rotatory ◽  
Guanidinium Chloride ◽  
Dispersion Parameters ◽  
Low Concentrations

1. The denaturation of ovalbumin by the reagents sodium dodecyl sulphate and guanidinium chloride was investigated, by following the changes in sedimentation velocity, optical rotatory dispersion and viscosity as a function of denaturant concentration. 2. With sodium dodecyl sulphate both the optical-rotatory-dispersion parameters a0 and b0 become more negative, the sedimentation coefficient decreases and the viscosity increases; significant differences in the denaturation profiles are observed. The change in each parameter is indicative of only limited denaturation. 3. With guanidinium chloride the transition occurs over the concentration range 1–4m: more extensive changes occur in all the physical parameters than with sodium dodecyl sulphate. The values of a0 and b0 are indicative of complete denaturation. Reduction by mercaptoethanol produces only minor further changes. 4. Renaturation was attempted from both denaturants, the removal of reagent being accomplished reversibly by controlled slow dialysis. Partial renaturation was observed, but aggregated or insoluble material was produced in both cases at relatively low concentrations of denaturant. Similar behaviour was observed with fully reduced protein in guanidinium chloride–mercaptoethanol; complete renaturation could not be brought about even at very low protein concentrations.

On the use of the n-propylammonium and n-butylammonium salts of d-10-camphorsulfonic acid for the calibration of spectropolarimeters: the concentration and solvent dependency of the optical rotatory dispersion parameters

1976 ◽  
Vol 54 (20) ◽  
pp. 3200-3202
Author(s):  
Yasushi Nakagawa ◽  
Michael F. Gillen ◽  
Ross E. Williams
Keyword(s):  
Ammonium Salts ◽  
Optical Rotatory Dispersion ◽  
Rotatory Dispersion ◽  
Optical Rotatory ◽  
Dispersion Parameters ◽  
Camphorsulfonic Acid ◽  
Concentration Dependency ◽  
Circular Dichroic

The utility of the title ammonium salts for the calibration of ord spectropolarimeters has been investigated. The solvent and concentration dependency of the measured specific molar rotations at 306 and 270 nm suggest that they may be used for calibration purposes only under well-defined conditions. The results of the Kramers–Kronig transformation of their circular dichroic spectra are presented and compared with the measured ord spectra.

scholarly journals Further studies on the thiol groups of human haemoglobin

1966 ◽  
Vol 101 (3) ◽  
pp. 741-746 ◽  
Author(s):  
A Adler ◽  
R Cecil
Keyword(s):  
Conformational Changes ◽  
Optical Rotatory Dispersion ◽  
Rotatory Dispersion ◽  
Optical Rotatory ◽  
Thiol Groups ◽  
Human Haemoglobin ◽  
Sh Groups ◽  
Derivatives Of ◽  
Haemoglobin Molecule

When the SH groups of various derivatives of human haemoglobin are converted into their mercuric mercaptides small changes are observed in the optical rotatory dispersion in the range 385-294mmu. These changes are proportionately greater for the reactive than for the unreactive SH groups. These observations have been interpreted in terms of the conformational changes that are likely to occur in the haemoglobin molecule on modification of the SH groups.

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