Modulation in the photosensitivity of albumin-bound bilirubin.
Exposure of BR-albumin complexes to visible light at pH 8.0 led to a change in the fluorescence intensity at 525 nm, which was found to be different for different serum albumins. Whereas a complex of BR with human serum albumin (HSA) showed a marked increase in fluorescence upon photoirradiation, BR-sheep serum albumin (SSA) complex failed to produce a marked increase. On the other hand, a complex of pig serum albumin (PSA) with BR produced a remarkable decrease in fluorescence upon photoirradiation. Equilibration of these complexes with approximately 20 mM chloroform for 1 h resulted in alteration in the photoinduced fluorescence. These photoinduced fluorescence modulations were found to be concentration dependent. Photoirradiation of BR-HSA complex led to a significant decrease in the positive CDCEs of the bisignate CD spectra in a time dependent manner that can be reconciled, to a significant extent, in the presence of chloroform. Taken together, all these results suggest that chiroptical properties/stability of albumin-bound BR varies with albumin species, protein concentration and the presence of chloroform.
Tayyab
S
S
Interdisciplinary Biotechnology Unit, Aligarh Muslim University, 202002, UP, Aligarh, India. btisamua@nde.vsnl.net.in
Paliwal
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P
Khan
M M
MM
D000418:Albumins / Q000737:chemistry* / Q000378:metabolism*; D000818:Animals; D001663:Bilirubin / Q000737:chemistry* / Q000378:metabolism*; D002725:Chloroform / Q000494:pharmacology; D002942:Circular Dichroism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008027:Light; D011485:Protein Binding; D012709:Serum Albumin / Q000737:chemistry; D012756:Sheep; D013997:Time Factors
D000418:Albumins; D012709:Serum Albumin; D002725:Chloroform; D001663:Bilirubin