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FLUORESCENCE PROPERTIES OF PORPHYRIN‐GLOBIN FROM HUMAN HEMOGLOBIN
Author(s) -
Sebban Pierre,
Coppey Maïté,
Alpert Bernard,
Lindqvist Lars,
Jameson David M.
Publication year - 1980
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.1751-1097.1980.tb04049.x
Subject(s) - porphyrin , fluorescence , chemistry , photochemistry , aqueous solution , globin , hemoglobin , quantum yield , tryptophan , heme , organic chemistry , amino acid , biochemistry , physics , quantum mechanics , enzyme
— Fluorescence excitation and emission spectra, decays, and quantum yields are reported for the porphyrin‐globin of hemoglobin (Hb desFe ) in aqueous solution of pH 8, at 4°C. A very weak fluorescence was observed in the UV (maximum at 334 nm), due to tryptophan and tyrosine residues, in addition to the strong porphyrin emission in the visible (maxima at 624 and 692 nm) reported previously. The absorption and fluorescence properties of the porphyrins of Hb desFe were compared to those for free porphyrin in organic solvents and in aqueous solution. The close similarity of the fluorescence decays and quantum yields in Hb desFe and in solution indicate the absence of stronger, specific porphyrin‐protein interactions; however, slight spectral shifts point to the existence of water molecules in the Hb desFe porphyrin environment. The fluorescence study also demonstrates the existence of efficient Trp‐porphyrin energy transfer of Förster type. The extent of transfer is in satisfactory agreement with the value expected from crystallographic data for hemoglobin. The results are discussed and compared to previous fluorescence studies of hemoglobin and apohemoglobin. An improved method for the preparation of Hb desFe is reported.