Kinetics of dimerization of the variable fragment of the Bence-Jones protein Au

The dimerization of the variable fragment of the Bence-Jones protein Au was examined in phosphate buffers at pH 6.8-6.9 And ionic strength of 0.1 M or 0.2 M at 20 degrees C. The dimerization constant was about 1 X 10(5) M-1. The reaction enthalpy was positive and the process was entropy driven. The association and dissociation rate constants were 9 X 10(6) M-1 s-1 and 1.5 X 10(2) s-1 respectively. Temperature-jump experiments exhibited the presence of two isomers of the dimer, which are present at equilibrium in a ratio of about 1:1. Isomerization occurred with a half-life of about 0.1 s.