Yukio Kubota

Fluorescence decay and quantum yield characteristics of acridine orange and proflavine bound to DNA

Fluorescence properties (quantum yield, decay curve, lifetime and polarization) of acridine orange and proflavine bound to DNA were examined as a function of nucleotide to dye (P/D) ratio. First, mean fluorescence lifetimes were determined by the phase-shift measurements. The lifetime and quantum yield of acridine orange increased in a parallel fashion with increasing P/D ratio. There was no parallel relation between the lifetime and quantum yield for proflavine; the lifetime showed a minimum around P/D equals 10...

A comparative study on bovine α-lactalbumin and lysozyme by nanosecond fluorometry

Analysis of the time decay of fluorescence anisotropy of 1-dimethylaminoaphthalene-5-sulfonyl (DNS) and fluorescamine derivatives of bovine alpha-lactalbumin and lysozyme reveals that no significant differences in mean rotational relaxation times are present. While fluorescamine molecules appear to orient randomly on these proteins, DNS is bound with a preferential orientation. Other fluorescence characteristics of the labels are also cited.

Fluorescence studies of the interaction between 1,N6-ethenoadenosine monophosphate and nucleotides

AMP, GMP, TMP and CMP quench the fluorescence of 1,N6-ethenoadenosine monophosphate (epsilon-AMP). The fluorescence spectrum of epsilon-AMP-nucleotide system is identical with that of epsilon-AMP itself, and the fluorescence decay kinetics follow a single-exponential decay law. The dependence of fluorescence yields and lifetimes upon the concentration of nucleotides shows that the fluorescence of epsilon-AMP is principally quenched in a dynamic process by AMP, TMP and CMP, while it is quenched in both dynamic and static processes by GMP. The quenching constants increase in the following order: GMP greater than AMP greater than TMP greater than CMP.