Chauvin F, Toptygin D, Roseman S, Brand L
Department of Biology, Johns Hopkins University, Baltimore, MD 21218.
Biophys Chem. 1992 Oct;44(3):163-73. doi: 10.1016/0301-4622(92)80049-b.
Enzyme I of the bacterial phosphotransferase system can exist in a monomer/dimer equilibrium which may have functional significance. Each monomer contains two tryptophan residues. It is demonstrated that the decay of both the monomer and the dimer can be described by a biexponential. The decay times depend on the temperature and at 6 degrees C the decay times are tau 1 = 0.4 ns and tau 2 = 3.2 ns for the monomer and tau 3 = 3.2 ns and tau 4 = 7.2 ns for the dimer form of the enzyme. The changes in the fluorescence decay parameters can be utilized to measure the equilibrium constant for the monomer/dimer transition.
细菌磷酸转移酶系统的酶I可以以单体/二聚体平衡的形式存在，这可能具有功能意义。每个单体含有两个色氨酸残基。结果表明，单体和二聚体的衰变都可以用双指数来描述。衰变时间取决于温度，在6摄氏度时，酶的单体形式的衰变时间为τ1 = 0.4纳秒和τ2 = 3.2纳秒，二聚体形式的衰变时间为τ3 = 3.2纳秒和τ4 = 7.2纳秒。荧光衰变参数的变化可用于测量单体/二聚体转变的平衡常数。
