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 Ligand-apomyoglobin interactions. Configurational adaptability of the haem-binding site

1976 ◽  
Vol 155 (3) ◽  
pp. 669-678 ◽  
Author(s):  
K E Lind ◽  
J V Møller
Keyword(s):  
Serum Albumin ◽  
Protoporphyrin Ix ◽  
Association Constants ◽  
The Other ◽  
Optical Rotatory Dispersion ◽  
Rotatory Dispersion ◽  
Bromophenol Blue ◽  
Optical Rotatory ◽  
Binding Studies ◽  
High Affinity

1. The interaction of the haem-binding region of apomyoglobin with different ligands was examined by ultrafiltration, equilibrium dialysis and spectrophotometry, to study unspecific features of protein-ligand interactions such as they occur in, for example, serum albumin binding. 2. Apomyoglobin, in contrast with metmyoglobin, binds at pH 7, with a high affinity, one molecule of Bromophenol Blue, bilirubin and protoporphyrin IX, two molecules of n-dodecanoate and n-decyl sulphate and four molecules of n-dodecyl sulphate and n-tetradecyl sulphate. 3. The number of high-affinity sites and/or association constants for the alkyl sulphates are enhanced by an increase of hydrocarbon length, indicating hydrophobic interactions with the protein. 4. Measurements of the temperature-dependence of the association constants of the high-affinity sites imply that the binding processes are largely entropy-driven. 5. Binding studies in the presence of two ligands show that bilirubin plus Bromophenol Blue and dodecanoate plus Bromophenol Blue can be simultaneously bound by apomyoglobin, but with decreased affinities. By contrast, the apomyoglobin-protoporphyrin IX complex does not react with Bromophenol Blue. 6. Optical-rotatory-dispersion measurements show that the laevorotation of apomyoglobin is increased towards that of metmyglobin in the presence of haemin and protoporphyrin IX. Small changes in the optical-rotatory-dispersion spectrum of apomyoglobin are observed in the presence of the other ligands. 7. It is concluded that the binding sites on apomyoglobin probably do not pre-exist but appear to be moulded from predominantly non-polar amino acid residues by reaction with hydrophobic ligands. 8. Comparison with data in the literature indicates that apomyoglobin on a weight basis has a larger hydrophobic area avaialble for binding of ligands than has human serum albumin. On the other hand, the association constants of serum for the ligands used in this study are generally somewhat larger than those of apomyoglobin.

A Study of the Pfeiffer Effect in Systems containing Trisoxalatometallate(III) Complexes and Cinchonine Hydrochloride

1971 ◽  
Vol 49 (12) ◽  
pp. 2161-2165 ◽  
Author(s):  
K. T. Kan ◽  
D. G. Brewer
Keyword(s):  
Dispersion Curves ◽  
Active Species ◽  
Optically Active ◽  
The Other ◽  
Optical Rotatory Dispersion ◽  
Rotatory Dispersion ◽  
Optical Rotatory ◽  
Cotton Effects ◽  
Equilibrium Shift ◽  
Complex Ion

The Pfeiffer effect was studied in systems containing cinchonine hydrochloride and trisoxalatometallate(III) complexes of Al, Fe, Cr, Co, and Ir. The Pfeiffer rotatory dispersion curves of the Cr and Co complexes show Cotton effects analogous to that observed in the optical rotatory dispersion (o.r.d.) curves of the respective complexes. The source of the Pfeiffer effect in all these systems is attributed either to an association between the complex ion and the optically active species in solution alone, as in the case of the Ir(lII) complex, or to a combination of this association and an "equilibrium shift" between the two enantiomers in solution in favor of one of them, as in the case of the other complexes under investigation.

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.

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