Acta Phys. -Chim. Sin. ›› 1998, Vol. 14 ›› Issue (07): 615-619.doi: 10.3866/PKU.WHXB19980708

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Determination of Enthalpy and Volume Changes in Photolysis of Coenzyme B12 Using Photoacoustic Calorimetry

Li Gang, Luo Lai-Bin, Chen Hui-Lan, Fu Shao-Wei, Zhang Shu-Yi   

  1. State Key Laboratory of Coordination Chemistry,Nanjing University,Nanjing 210093|Laboratory of Modern Acoustics and Institute of Acoustics,Nanjing University,Nanjing 210093
  • Received:1997-10-27 Revised:1998-02-23 Published:1998-07-15
  • Contact: Chen Hui-Lan;

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Abstract:

The photolysis of coenzyme B12 (5'-deoxyadenosylcobalamin, AdoCbl) at 355nm in aqueous solution is investigated by Photoacoustic Calorimetry (PAC). Both enthalpy and reaction volume change for this photoinitiated reaction have been determined to be 131±12 kJ.mol-1 and 61 mLmol-1 , respectively. It can be suggested that the reaction volume change is related tothe conformational change of corrin ring which accompanies the homolytic cleavage of the cobalt-carbon(Co-C) bond.

Key words: Coenzyme B12, Photoacoustic calorimetry, Enthalpy, Volume change