scholarly journals Raman spectroscopic analysis of high molecular weight proteins in solution – considerations for sample analysis and data pre-processing

The Analyst ◽  
2018 ◽  
Vol 143 (24) ◽  
pp. 5987-5998 ◽  
Author(s):  
Drishya Rajan Parachalil ◽  
Brenda Brankin ◽  
Jennifer McIntyre ◽  
Hugh J. Byrne

This study explores the potential of Raman spectroscopy, coupled with multivariate regression techniques and ion exchange chromatography, to quantitatively monitor diagnostically relevant changes in high molecular weight proteins in liquid plasma.

1984 ◽  
Vol 62 (6) ◽  
pp. 449-455 ◽  
Author(s):  
Show-Jy Lau ◽  
Bibudhendra Sarkar

The binding of six trace metals, Mn(II), Ni(II), Zn(II), Cu(II), Cd(II) and Fe(III), to human cord serum has been studied by Sephadex G-100 gel filtration at physiological pH, using radioisotopes as tracers. The results are compared with those obtained from adult serum. In both cord and adult sera, extensive amounts of the metals are bound to high molecular weight proteins. Among them, Fe(III) is mostly bound to transferrin; Ni(II), Zn(II), Cu(II), and Cd(II) are bound to albumin and other macro-molecules. The binding of Mn(II) either to transferrin or albumin is not resolved. Small fractions of Zn(II), Cu(II), and Cd(II) and large fractions of Mn(II) and Ni(II) are found to be associated with low molecular weight components of both sera. The distribution varies from metal to metal. However, the low molecular weight component of the size 1500 – 10 000 is present in all the metals studied. Further purification of this component was attempted by DEAE-cellulose ion-exchange chromatography. The possible identity as well as the biological role played by this particular component of serum in the transport of metals in blood and across membranes is discussed.


Blood ◽  
1983 ◽  
Vol 62 (5) ◽  
pp. 1123-1131 ◽  
Author(s):  
BN Bouma ◽  
RA Vlooswijk ◽  
JH Griffin

Abstract Coagulation factor XI was purified from human plasma using ion-exchange chromatography and affinity chromatography on high molecular weight kininogen-Sepharose. A monospecific precipitating antiserum was prepared and used to study factor XI antigen. Factor XI did not migrate during electrophoresis at pH 8.3. High molecular weight kininogen (HMWK), an alpha globulin, reversibly associates with factor XI. Complex formation between HMWK and factor XI was observed under conditions of crossed-immunoelectrophoresis. Using Laurell rocket immunoelectrophoresis, it was shown that the isolated alkylated light chain of kinin-free HMWK formed a complex with factor XI. In contrast to previous studies of prekallikrein, titrations of factor XI with increasing amounts of HMWK did not give a simple titration curve, suggesting that factor XI dissociates from the complex during electrophoresis. Prekallikrein and factor XI were shown to compete for the same HMWK molecules under the conditions of immunoelectrophoresis, and prekallikrein appeared to have a higher affinity for binding to HMWK than factor XI. Quantitative determinations of factor XI antigen in plasma by rocket immunoelectrophoresis were made. The average amount of factor XI measured in plasma samples from 20 normal individuals was 4.5 micrograms/ml (range 3–6). No factor XI antigen was detected in plasma from a patient deficient in factor XI. Normal factor XI antigen levels were detected in 3 different HMWK-deficient plasmas only if the plasmas were reconstituted with purified HMWK (2 U/ml). Addition of HMWK to normal plasma resulted in an increase of the factor XI antigen rocket. At HMWK levels of 2 U/ml, no further increase of the factor XI antigen rocket was observed. Therefore, accurate measurement of factor XI antigen by rocket immunoelectrophoresis is possible only if an excess of HMWK is present.


Blood ◽  
1983 ◽  
Vol 62 (5) ◽  
pp. 1123-1131
Author(s):  
BN Bouma ◽  
RA Vlooswijk ◽  
JH Griffin

Coagulation factor XI was purified from human plasma using ion-exchange chromatography and affinity chromatography on high molecular weight kininogen-Sepharose. A monospecific precipitating antiserum was prepared and used to study factor XI antigen. Factor XI did not migrate during electrophoresis at pH 8.3. High molecular weight kininogen (HMWK), an alpha globulin, reversibly associates with factor XI. Complex formation between HMWK and factor XI was observed under conditions of crossed-immunoelectrophoresis. Using Laurell rocket immunoelectrophoresis, it was shown that the isolated alkylated light chain of kinin-free HMWK formed a complex with factor XI. In contrast to previous studies of prekallikrein, titrations of factor XI with increasing amounts of HMWK did not give a simple titration curve, suggesting that factor XI dissociates from the complex during electrophoresis. Prekallikrein and factor XI were shown to compete for the same HMWK molecules under the conditions of immunoelectrophoresis, and prekallikrein appeared to have a higher affinity for binding to HMWK than factor XI. Quantitative determinations of factor XI antigen in plasma by rocket immunoelectrophoresis were made. The average amount of factor XI measured in plasma samples from 20 normal individuals was 4.5 micrograms/ml (range 3–6). No factor XI antigen was detected in plasma from a patient deficient in factor XI. Normal factor XI antigen levels were detected in 3 different HMWK-deficient plasmas only if the plasmas were reconstituted with purified HMWK (2 U/ml). Addition of HMWK to normal plasma resulted in an increase of the factor XI antigen rocket. At HMWK levels of 2 U/ml, no further increase of the factor XI antigen rocket was observed. Therefore, accurate measurement of factor XI antigen by rocket immunoelectrophoresis is possible only if an excess of HMWK is present.


1970 ◽  
Vol 117 (2) ◽  
pp. 369-375 ◽  
Author(s):  
Nils-Georg Asp

1. Different forms of the rat small-intestinal ‘acid’ β-galactosidase were separated by using the isoelectric-focusing technique. The isoelectric points of the different forms were at pH4.2, 4.6, 5.4, 6.1 and approx. 8. 2. The two forms of ‘acid’ β-galactosidase isoelectric at pH4.2 and 4.6 were completely excluded from the Sephadex G-200 gel, whereas the form isoelectric at pH8 had Kav. 0.4. The concentration and pH of the elution buffer influenced the distribution of enzyme activity between different forms. Thus, under certain conditions of ionic strength and pH, the enzyme seems to form high-molecular-weight aggregates with low isoelectric points. These may be homopolymeric aggregates or the result of binding of enzyme to, for example, membrane fragments. The forms isoelectric at pH5.4 and 6.1 are probably aggregates of intermediate size. 3. During ion-exchange chromatography at pH6.0 one fraction of ‘acid’ β-galactosidase was not retained on the column and was isoelectric at pH8 and another fraction was eluted when the buffer concentration in the eluate had increased to about 50mm. The main part of enzyme eluted in this second fraction was also isoelectric at pH8, indicating that the elution of this fraction is not a simple ion-exchange procedure but probably also involves a splitting of high-molecular-weight aggregates, originally retained because of their low isoelectric points. The enzyme subunits have a higher isoelectric point, and are therefore no longer bound to the ion-exchange resin.


1973 ◽  
Vol 72 (2) ◽  
pp. 235-242 ◽  
Author(s):  
A. M. Reuter ◽  
J. C. Hendrick ◽  
J. Sulon ◽  
P. Franchimont

ABSTRACT The percentage of LH* bound to antibodies that have been covalently bound to cellulose is diminished in the presence of LH-free human serum and sera from various species of animals. Serum fractionation studies on Sephadex G 200 show that the greatest interference comes from the proteins eluted in the void volume i. e. the high molecular weight proteins. Specifically, the gamma M globulins and the α2-macroglobulins appear to play an important role, as demonstrated by tests in which these proteins were neutralized by gamma M and α2-macroglobulin antisera.


2010 ◽  
Vol 49 (11) ◽  
pp. 1958-1962 ◽  
Author(s):  
Pierre Gans ◽  
Olivier Hamelin ◽  
Remy Sounier ◽  
Isabel Ayala ◽  
M. Asunción Durá ◽  
...  

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