Acta Phys. -Chim. Sin. ›› 2017, Vol. 33 ›› Issue (5): 1051-1056.doi: 10.3866/PKU.WHXB201702201

• ARTICLE • Previous Articles     Next Articles

Reactions of Triplet-State Difloxacin with Amino Acids and dGMP: A Laser Flash Photolysis Study

Hai-Xia LI1,Yan-Cheng LIU2,Rui-Zhi TANG2,Peng ZHANG2,Liu-Kui MA1,Chi-Yuan WEI1,Wen-Feng WANG2,*()   

  1. 1 Pujiang Institute, Nanjing Tech University, Nanjing 211132, P. R. China
    2 Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, P. R. China
  • Received:2016-11-18 Published:2017-04-20
  • Contact: Wen-Feng WANG
  • Supported by:
    The project was supported by the National Natural Science Foundation of China(21173252)


The reactions of triplet-state difloxacin (DFX) with various amino acids and deoxyguanylic acid in aqueous media were studied using laser flash photolysis. Tryptophan, tyrosine, cysteine, and 2'-deoxyguanosine-5'-monophosphate (dGMP) were found to completely quench the triplet state of DFX in aqueous solution, the corresponding second-order rate constants being 1.97×108, 1.48×108, 1.72×108, and 6.92×107 dm3·mol-1·s-1. The quenching mechanism involves electron transfer to the photoexcited triplet state of DFX from the tryptophan, tyrosine, cysteine, and dGMP moieties, followed by fast protonation of the resulting DFX anion radical.

Key words: Laser flash photolysis, Difloxacin, Triplet state, Amino acid


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