THE MOLECULAR WEIGHT OF HAEMATOPORPHYRIN DERIVATIVE, ITS GEL COLUMN FRACTIONS and SOME OF ITS COMPONENTS IN AQUEOUS SOLUTION |
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Authors: | A. Geoffrey Swincer A. David Ward Geoffrey J. Howlett |
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Affiliation: | Department of Organic Chemistry, University of Adelaide, Adelaide, South Australia. 5000.;The Russell Grimwade School of Biochemistry, University of Melbourne. Parkville. Victoria. Australia. |
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Abstract: | Abstract— The average molecular weights of haematoporphyrin derivative (HPD), the fractions of HPD that can he obtained by gel chromatography and of purified haematoporphyrin and protoporphyrin in aqueous solution have been determined by ultracentrifugation. The results show that HPD contains polymeric material with the excluded fraction from the gel column (HPD aggregate) having an average molecular weight of greater than 20000. The two remaining gel column fractions of HPD have lower molecular weights and their similarity indicates that these fractions do not separate because of molecular weight differences. Purified haematoporphyrin has a comparatively low molecular weight in aqueous solution but the data is not capable of discriminating between monomer, dimer or slightly higher oligomer. In contrast, protoporphyrin sediments to the bottom of the centrifuge tube under the conditions of sedimentation equilibrium indicating that it has an average molecular weight considerably greater than that of HPD aggregate. |
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