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EFFECT OF U.V.‐IRRADIATION ON SEDIMENTATION BEHAVIOR OF VARIOUS PROTEINS
Author(s) -
Dose Klaus,
Sena Luigi
Publication year - 1968
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1968.tb05829.x
Subject(s) - ultracentrifuge , dissociation (chemistry) , sedimentation , chemistry , irradiation , protein quaternary structure , molecule , enzyme , dissociation constant , biophysics , chromatography , biochemistry , biology , physics , organic chemistry , nuclear physics , paleontology , receptor , protein subunit , sediment , gene
— Moderate u.v.‐doses (2537 Å) sufficient to reduce enzymatic activities of native enzymes up to about 90 per cent, in general do not produce measurable amounts of smaller dialyzable fragments. The disappearance of the original boundary in sedimentation diagrams is mostly due to the formation of rapidly sedimenting polydispersed material. Generally the sedimentation constants of the native proteins are not significantly changed. The boundaries, however, often loose their symmetry. The quantum yields for the disappearance of the original boundaries are roughly inversely proportional to the molecular weights. The number of molecules disappearing from the main peak is smaller than the number of molecules inactivated by a given dose. The data indicate that ultracentrifugation provides no satisfactory method for separation of native molecules from the damaged and inactivated. Proteins with labile quaternary structures (e.g. thyroglobulin or hemocyanine) which tend to dissociate under very mild conditions show an enhanced dissociation after u. v.‐irradiation.