[Effect of serotonin on the yield of UV-induced thymine dimers in DNA]

Using a fluorescence method the interaction between serotonin and DNA has been investigated and the association constant Kc = 4.2 X 10(4) M-1 was determined. Bound serotonin is shown to reduce the yield of UV-induced thymine dimers in DNA. It is calculated that the value of the effective distance over which each protector acts is a segment of the DNA helix about four base pairs long.