Photochemistry and Photobiology p. 735 - 741 (1996)
Update date:2022-08-17
Topics:
Krylov, Sergey N.
Dunford, H. Brian
The inhibition of horseradish peroxidase (HRP)-catalyzed oxidation of indole-3-acetic acid (IAA) by a phenol, caffeic acid (CA), was studied using both a kinetic approach and computer simulation. The presence of CA resulted in a lag period in IAA oxidation. The lag period increased slowly with increasing [CA] until a critical concentration, [CA]cr, was reached, then it increased much faster when [CA] was greater than [CA]cr The [CA]cr was proportional to [IAA] and did not depend upon [HRP]. Caffeic acid was oxidized by compound I and compound II of HRP with bimolecular rate constants (6.8 ± 107 and 2.1 ± 107 M-1s-1), which were much higher than the corresponding rate constants for IAA oxidation (2.3 ± 103 and 2.0 ±102 M-1s-1). Our experimental data show that CA inhibits IAA oxidation because it is able to compete effectively as a peroxidase substrate. A model based on a detailed mechanism of IAA oxidation was investigated using computer simulation. A rate constant driving nonenzymatic hydroperoxide formation in IAA solution was determined, 3.0 × 10-7 s-1. The model quantitatively describes the experimental results of this work and also qualitatively explains data published earlier. The critical inhibitor concentration is approximately equal to twice the concentration of hydroperoxide in IAA solution at the time of inhibitor addition. Therefore hydroperoxide concentration can be calculated from the determination of critical inhibitor concentration.
View MoreDalian Synco Chemical Co., Ltd.
Contact:+86-411-83635150
Address:Rm 1004, 24, Tangshan Street, Dalian
Contact:886 2 2541 0022
Address:8 Fl., No. 11, Sec. 1, Chung Shan North Rd., Taipei, Taiwan R.O.C.
Contact:+86-021-58123769
Address:No.780 of Cailun Road,Zhangjiang Hi-tech Park,Pudong,Shanghai
ZHIJIANG ZENVA SINO COMMERCE AND TRADE CO., LTD.
website:http://www.zenvasino.com
Contact:+86-138-72658998
Address:Shibeishan Road,Zhijiang, Hubei, China
Wuhan Fortuna Chemical Co.,Ltd
website:http://www.fortunachem.com
Contact:86-27-59207850
Address:Add: Room 2015, No.2 Building, Kaixin Mansion No.107 Jinqiao Avenue, Wuhan, China
Doi:10.1039/c4ra07688e
(2014)Doi:10.1016/j.cattod.2014.06.002
(2015)Doi:10.1016/S0040-4039(00)96798-4
(1987)Doi:10.1002/anie.201201848
(2012)Doi:10.3987/COM-10-S(E)126
(2011)Doi:10.1016/j.jfluchem.2017.04.007
(2017)