Kinetic and Thermodynamic Studies on Afp Binding to Afp Antibody in Colorectal Tumor Homogenates

  • Bilal J. M. Al Rawi University of Al Anbar
  • Sami A. Al Mudhaffar University of Baghdad
  • Hathama R. Hassan University of Baghdad
Keywords: The


Kinetic and thermodynamic parameters associated with the binding of 125I- anti AFP Antibody to AFP in both crude colorectal homogenate and partially- purified fractions were investigated. It was shown that the reaction in all studied groups follow pseudo- first order reaction kinetics.The value of kinetic parameters Ka, Kd, Kobs, K+1, K-1, (t1/2) ass., (t1/2)diss. and maximal binding capacity (Bmax) at 25oC for the binding of anti 125I-AFP antibody with its cytosolic antigen in benign colorectal tumor were found to be : 0.0543 x 1010 M-1, 15.064 x 10-10M, 0.0158 min-1, 4.086 x 106 M-1.min-1, 64.76x10-4 min-1, 43 min, 104.28 min and 29.14 Pmol/mg protein respectively, while 0.0538 x 1010 M-1, 15.142 x 10-10 M, 0.0163 min-1, 4.301 x 106 M-1.min-1, 67.63 x 10-4 min-1, 40 min, 79.66 min and 46.25 Pmol/mg respectively for the binding of anti 125I-AFP antibody with its cytosolic antigen in tissues of malignant colorectal tumor and at 4oC.  The maximum binding of partially purified AFP occurred at 25oC. The values ofKa and K+1 increased with increasing temperature. The Vant Hoff plot demonstrated linear relationship between lnKa and 1/T, using crude colorectal homogenate partially purified AFP as AFP source. Plotting between ln K+1 and 1/T gave linear relationship called Arrheniuns relationship. The thermodynamic parameters ΔΗ˚, ΔG˚ and ΔЅ˚ for the formation of (125I- anti AFP Antibody / AFP) complex at the standard state had been determinedas well asEa, ΔΗ*, ΔG* and ΔЅ* which representing the transition state.

Author Biographies

Bilal J. M. Al Rawi, University of Al Anbar

Chemistry Dept., Education College for women, Al Anbar University

Sami A. Al Mudhaffar, University of Baghdad

Chemistry Dept., College of Science, University of Baghdad

Hathama R. Hassan, University of Baghdad

Chemistry Dept., College of Science, University of Baghdad


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How to Cite
Al Rawi, B., Al Mudhaffar, S., & Hassan, H. (2013). Kinetic and Thermodynamic Studies on Afp Binding to Afp Antibody in Colorectal Tumor Homogenates. Science Journal of University of Zakho, 1(2), 699-714. Retrieved from
Science Journal of University of Zakho