Serum albumin binding sites properties in donors and in schizophrenia patients: the study of fluorescence decay of the probe K-35 using S-60 synchrotron pulse excitation

The properties of serum albumin obtained from donors and from paranoid schi zophrenia patients were studied with the fluorescent probe K-35 (N-carboxyp henylimide of dimethylaminonaphthalic acid) and time-resolved fluorescence spectroscopy on the SR beam station of the S-60 synchrotron of the Lebedev Physical Institute. The mean fluorescence quantum yield of K-35 in patients serum was decreased significantly by 25-60% comparing with donors. The ana lysis of pre-exponential factors of fluorescence decay using "amplitude sta ndard" method has shown that in patient sera the fraction of K-35 molecules bound with albumin and inaccessible to fluorescence quenchers ("bright" K- 35 molecules with tau(1) = 8.0 +/- 0.4 ns) is 1.2-3 times less than in the donor sera. The fraction of K-35 molecules with partly quenched fluorescenc e (tau(2) = 1.44 +/- 0.22 ns) was significantly increased in schizophrenia patients. The results obtained suggest that the properties of binding regio n in serum albumin molecules of acute paranoid schizophrenia patients chang e significantly. (C) 2000 Elsevier Science B.V. All rights reserved.