Sil Susmita, Chakraborti Abhay Sankar
Department of Biophysics, Molecular Biology & Genetics, University College of Science, University of Calcutta, 92, Acharyya Prafulla Chandra Road, Kolkata 700009, India.
Int J Biol Macromol. 2005 Jul;36(1-2):16-22. doi: 10.1016/j.ijbiomac.2005.03.003.
Spectrofluorimetric and spectrophotometric studies were done to understand the binding of hematoporphyrin, a photosensitizer to horseradish peroxidase (EC1.11.1.7). The binding affinity constant (K) decreases as the state of aggregation of the porphyrin increases, while the number of binding sites (approximately 1) remains unchanged. The interaction appears to be mostly hydrophobic, entropy-driven and endothermic process. Hematoporphyrin potentiates horseradish peroxidase-catalyzed H2O2-mediated NADH oxidation, probably by porphyrin-influenced removal of superoxide radicals, which are generated in the system. Conformational change of the protein due to its interaction with porphyrin may be associated with potentiation of the catalytic activity of the enzyme.
进行了荧光分光光度法和分光光度法研究，以了解光敏剂血卟啉与辣根过氧化物酶（EC1.11.1.7）的结合情况。随着卟啉聚集状态的增加，结合亲和常数（K）降低，而结合位点的数量（约为1）保持不变。这种相互作用似乎主要是疏水的、熵驱动的吸热过程。血卟啉增强了辣根过氧化物酶催化的H2O2介导的NADH氧化，这可能是由于卟啉影响了系统中产生的超氧自由基的清除。蛋白质由于与卟啉相互作用而发生的构象变化可能与酶催化活性的增强有关。
