The interaction between captopril, an inhibitor of angiotensin converting enzyme and human serum albumin, a principal plasma protein in the liver has been investigated in vitro under a simulated physiological condition by UV-vis spectrophotometry and fluorescence spectrometry. The intrinsic fluorescence intensity of human serum albumin was strongly quenched by captopril. The binding constants and the number of binding sites can be calculated from the data obtained from fluorescence quenching experiments. The negative value of Δ<i>G<sup>0</sup></i> reveals that the binding process is a spontaneous process. According to the van’t Hoff equation, the standard enthalpy change (Δ<i>H<sup>0</sup></i>) and standard entropy change (Δ<i>S<sup>0</sup></i>) for the reaction were calculated to be 35.98 KJ●mol<sup>-1</sup> and 221.25 J●mol<sup>-1</sup> K. It indicated that the hydrophobic interactions play a main role in the binding of captopril to human serum albumin. In addition, the distance between captopril (acceptor) and tryptophan residues of human serum albumin (donor) was estimated to be 1.05 nm according to the Förster’s resonance energy transfer theory. The results obtained herein will be of biological significance in pharmacology and clinical medicine.
KeywordsHuman Serum AlbuminCaptoprilFluorescence QuenchingStern-Volmer EquationThe Förster’s Resonance Energy Transfer Theory
[1] A. Gupta, S. K. Prajapati, M. Singh and M. Balamurugan, “Proniosomal Powder of Captopril: Formulation and Evaluation,” Molecular Pharmaceutics, Vol. 4, No. 4, May 2007, pp. 596-599. doi:10.1021/mp0700110
J. K. Wang, L. Gao and Y. Liu, “Solubility of Captopril in 2-Propanol, Acetone, Acetonitrile, Methyl Acetate, Ethyl Acetate, and Butyl Acetate,” Journal of Chemical & Engineering Data, Vol. 55, No. 2, October 2010, pp. 966-967. doi:10.1021/je900401z
L. S. Milner, M. Yuskiw, A. Sadeghi-Nejad and M. A. Linshaw, “Captopril Reduces the Proteinuric Effect of Human Growth Hormone in Adriamycin Nephrosis,” Pediatric Nephrology, Vol. 13, No. 5, June 1999, pp. 391-395. doi:10.1007/s004670050628
G. R. Jan Elferink and M. Ben de Koster, “Modulation of Neutrophil Migration by Captopril, Naunyn-Schmiedeberg’s Arch,” Pharmacol, Vol. 347, No. 5, May 1993, pp. 562-567. doi:10.1007/BF00166751
Y. G. Wang and Z. Y. Lu, “Effect of Captopril on Membrane Currents of Ventricular Myocytes,” Journal of Tongji Medical University, Vol. 15, No. 4, May 1995, pp. 209-211. doi:10.1007/BF02887946
C. Ribuot and L. Rochette, “Converting Enzyme Inhibitors (Captopril, Enalapril, Perindopril) Prevent Early-Post Infarction Ventricular Fibrillation in The Anaesthetized Rat,” Cardiovascular Drugs and Therapy, Vol. 1, No. 1, January 1987, pp. 51-55. doi:10.1007/BF02125833
A. Karimia and N. Alizadehb, “Rapid Analysis of Captopril in Human Plasma and Pharmaceutical Preparations by Headspace Solid Phase Microextraction based on Polypyrrole Film Coupled to Ion Mobility Spectrometry,” Talanta, Vol. 79, No. 2, July 2009, pp. 479-485. doi:10.1016/j.talanta.2009.04.016
F. L. Cui, Y. R. Cui, H. X. Luo, X. J. Yao, J. Fan and Y. Lu, “Interaction of APT with BSA or HAS,” Chinese Science Bulletin, Vol. 51, No. 18, September 2006, pp. 2201-2207. doi:10.1007/s11434-006-2108-y
A. K. Shaw and S. K. Pal, “Spectroscopic Studies on the Effect of Temperature on pH-Induced Folded States of Human Serum Albumin,” Journal of Photochemistry and Photobiology B: Biology, Vol. 90, No. 1, January 2008, pp. 69-77.
Z. Lu, Y. Zhang, H. Liu, J. Yuan, Z. Zheng and G. Zou, “Transport of a Cancer Chemopreventive Polyphenol, Resveratrol: Interaction with Serum Albumin and Hemoglobin,” Journal of Fluorescence, Vol. 17, No. 5, September 2007, pp. 580-587. doi:10.1007/s10895-007-0220-2
Y. J. Hu, Y. Liu and L. X. Zhang, “Study of Interaction between Colchicines and Bovine Serum Albumin by Fluorescence Quenching Method,” Journal of Molecular Structure, Vol. 750, No. 1-3, August 2005, pp. 174-178. doi:10.1016/j.molstruc.2005.04.032
C. Dufour and O. Dangles, “Flavonoid-Serum Albumin Complexation: Determination of Binding Constants and Binding Sites by Fluorescence Spectroscopy,” Biochi- mica et Biophysica Acta, Vol. 1721, No. 1-3, January 2005, pp. 164-173.
M. X. Xie, M. Long, Y. Liu, C. Qin and Y. D. Wang, “Characterization of the Interaction between Human Serum Albumin and Morin,” Biochimica et Biophysica Acta, Vol. 1760, No. 8, August 2006, pp. 1184-1191.
H. G. Mahesha, S. A. Sighn, N. Srinivasan and R. G. Appu, “A Spectroscopic Study of the Interaction of Isoflavones with Human Serum Albumin,” Febs Journal, Vol. 273, No. 3, February 2006, pp. 451-467. doi:10.1111/j.1742-4658.2005.05071.x
I. Petitpas, A. A. Bhattacharya, S. Twine, M. East and S. Curry, “Crystal Structure Analysis of Warfarin Binding to Human Serum Albumin-Anatomy of Drug Site I,” The Journal of Biological Chemistry, Vol. 276, No. 25, June 2001, pp. 22804-22809. doi:10.1074/jbc.M100575200
F. Moreno, J. Gonza’lez-Jime′nez, “Binding of the Promen Fluorescent Probe to Human Serum Albumin: A Fluorescence Spectroscopic Study,” Chemico-Biological Interactions, Vol. 121, No. 3, August 1999, pp. 237-252. doi:10.1016/S0009-2797(99)00111-8
K. Yamasaki, T. Maruyama, U. Kragh-Hansen and M. Otagiri, “Characterization of Site I on Human Serum Albumin: Concept about the Structure of a Drug Binding Site,” Biochimica et Biophysica Acta, Vol. 1295, No. 2, July 1996, pp. 147-157. doi:10.1016/0167-4838(96)00013-1
J. R. Lakowicz, “Principles of Fluorescence Spectroscopy,” 2nd Edition, Plenum Press, New York, 1999.
O. R. Quayle, “The Parachors of Organic Compounds. In: an Interpretation and Catalogue,” Chemical Reviews, Vol. 53, No. 3, December 1953, pp. 439-589. doi:10.1021/cr60166a003
J. R. Lakowicz, “Principles of Fluorescence Spectroscopy,” Plenum Press, New York, 1983.
Y, B. Huang, B. Z. Liu, Z. Yu, X. Y. Gao and Y. Q. Zi, “Luminescence Quenching Effect for the Interaction of Prulifloxacin with Trypsin–Britton–Robinson Buffer Solution System,” Journal of Luminescence, Vol. 130, No. 3, March 2010, pp. 360-364.
H. W. Zhao, M. Ge, Z. X .Zhang, W. F. Wang and G. Z. Wu, “Spectroscopic Studies on the Interaction between Riboflavin and Albumins. Spectrochim,” Acta Part A, Vol. 65, No. 3-4, November 2006, pp. 811-817. doi:10.1016/j.saa.2005.12.038
J. H. Tang, S. D. Qi and X. G. Chen, “Spectroscopic Studies of the Interaction of Anti-Coagulant Rodenticide Diphacinone with Human Serum Albumin,” Journal of Molecular Structure, Vol. 779, No. 1-3, November 2005, pp. 87-95. doi:10.1016/j.molstruc.2005.07.023
J. R. Lakowicz and G. Weber, “Quenching of Fluorescence by Oxygen, Probe for Structural Fluctuations in Macromolecules,” Biochemistry, Vol. 12, No. 21, October 1973, pp. 4161-4170. doi:10.1021/bi00745a020
W. R. Ware, “Oxygen Quenching of Fluorescence in Solution: An Experimental Study of the Diffusion Process,” The Journal of Physical Chemistry, Vol. 66, No. 3, March 1962, pp. 455-458. doi:10.1021/j100809a020
X. Z. Feng, Z. Lin, L. J. Yang, C. Wang and C. L. Bai, “Investigation of the Interaction between Acridine Orange and Bovine Serum Albumin,” Talanta, Vol. 47, No. 5, December 1998, pp. 1223-1229.
M. Jiang, M. X. Xie, Y. Liu, X. Y. Li and X. Chen, “Spectroscopic Studies on the Interaction of Cinnamic Acid and Its Hydroxyl Derivatives with Human Serum Albumin,” Journal of Molecular Structure, Vol. 692, No. 1-3, April 2004, pp. 71-80. doi:10.1016/j.molstruc.2004.01.003
M. X. Xie, X. Y. Xu and Y. D. Wang, “Interaction between Hesperetin and Human Serum Albumin Revealed by Spectroscopic Methods,” Biochimica et Biophysica Acta, Vol. 1724, No. 1-2, June 2005, pp. 215-224.
P. B. Kandagal, S. Ashoka, J. Seetharamappa, S. T. Shaikh, Y. Jadegoud and O. B. Ijare, “Study of the Interaction of an Anticancer Drug with Human and Bovine Serum Albumin: Spectroscopic Approach,” Journal of Pharmaceutical and Biomedical Analysis, Vol. 41, No. 2, May 2006, pp. 393-399. doi:10.1016/j.jpba.2005.11.037
Y. L. Wei, J. Q. Li, C. Dong, S. Shuang, D. S. Liu and C. W. Hui, “Investigation of the Association Behaviors between Biliverdin and Bovine Serum Albumin by Fluorescence Spectroscopy,” Talanta, Vol. 70, No. 2, September 2006, pp. 377-382. doi:10.1016/j.talanta.2006.02.052
P. D. Ross and S. Subramanian, “Thermodynamics of Protein Association Reactions: Forces Contributing to Stability,” Biochemistry, Vol. 20, No. 11, May 1981, pp. 3096–3210. doi:10.1021/bi00514a017
T. F?rster, “Modern Quantum Chemistry,” In: O. Sinaoglu, Ed., Academic Press, New York, Vol. 3, 1965.
G. Cristobal, R. Dos and D. M. Pierre, “Fluorescence Resonance Energy Transfer Spectroscopy is a Reliable “Ruler” for Measuring Structural Changes in Proteins: Dispelling the Problem of the Unknown Orientation Factor,” Journal of Structural Biology, Vol. 115, No. 2, September 1995, pp. 175-185. doi:10.1006/jsbi.1995.1042
D. C. Saha, K. Ray and T. N. Misra, “Energy Transfer in Triton-X 100 Micelles: A Fluorescence Study,” Spectrochimica Acta Part A, Vol. 56, No. 4, March 2000, pp. 797-801. doi:10.1016/S1386-1425(99)00169-9
C. Bertucci and E. Domenici, “Reversible and Covalent Binding of Drugs to Human Serum Albumin: Methodological Approaches and Physiological Relevance,” Current Medicinal Chemistry, Vol. 9, No. 15, August 2002, pp. 1463-1481.
B. Valeur and J. C. Brochon, “New Trends in Fluorescence Spectroscopy,” 6th Edition, Springer Press, Berlin, 1999.
G. Z. Chen, X. Z. Huang, J. G. Xu, Z. X. Zheng and Z. B. Wang, “The Methods of Fluorescence Analysis (in Chinese),” 2nd Edition, Science in China Press, Beijing, 1990.