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Photoilluminated riboflavin/riboflavin-Cu(II) inactivates

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Field Value
 
Title Photoilluminated riboflavin/riboflavin-Cu(II) inactivates
 
Creator Husain, E
Fatima, R A
Ali, I A F
Naseem, I
 
Subject Riboflavin
Trypsin
Copper
Reactive oxygen species
 
Description 312-318
Riboflavin (RF) upon irradiation with fluorescent light generates reactive oxygen species like superoxide anion, singlet and triplet oxygen, flavin radicals and substantial amounts of hydrogen peroxide (H2O2). H2O2 can freely penetrate cell membrane and react with a transition metal ion like Cu(II), generating hydroxyl radical via the modified metal-catalyzed Haber-Weiss reaction. Earlier, it was reported that trypsin-chymotrypsin mixture served as an indirect antioxidant and decreased free radical generation. Thus, in the present study, we used photoilluminated RF as a source of ROS to investigate the effect of free radicals on the activity of trypsin. We also compared the damaging effect of photoilluminated RF and RF-Cu(II) system using trypsin as a target molecule. RF caused fragmentation of trypsin and the effect was further enhanced, when Cu(II) was added to the reaction. Results obtained with various ROS scavengers suggested that superoxide radical, singlet and triplet oxygen were predominantly responsible for trypsin damage caused by photoilluminated RF. On the other hand, when Cu(II) was added to the reaction, hydroxyl radical was mainly responsible for trypsin damage. A mechanism of generation of various ROS in the reaction is also proposed. Trypsin did not show any antioxidant effect with RF alone or with RF–Cu(II) combination.
 
Date 2009-03-20T05:24:33Z
2009-03-20T05:24:33Z
2006
 
Type Article
 
Identifier 0301-1208
http://hdl.handle.net/123456789/3409
 
Language en_US
 
Publisher CSIR
 
Source IJBB Vol.43(5) [October 2006]