451-13-8Relevant articles and documents
The structure of 4-hydroxylphenylpyruvate dioxygenase complexed with 4-hydroxylphenylpyruvic acid reveals an unexpected inhibition mechanism
Wang, Xiaoning,Lin, Hongyan,Liu, Junjun,Zhao, Xinyun,Chen, Xi,Yang, Wenchao,Yang, Guangfu,Zhan, Chang-guo
, p. 1920 - 1924 (2021)
4-Hydroxyphenylpyruvate dioxygenase (HPPD) is an important target for both drug and pesticide discovery. As a typical Fe(II)-dependent dioxygenase, HPPD catalyzes the complicated transformation of 4-hydroxyphenylpyruvic acid (HPPA) to homogentisic acid (HGA). The binding mode of HPPA in the catalytic pocket of HPPD is a focus of research interests. Recently, we reported the crystal structure of Arabidopsis thaliana HPPD (AtHPPD) complexed with HPPA and a cobalt ion, which was supposed to mimic the pre-reactive structure of AtHPPD-HPPA-Fe(II). Unexpectedly, the present study shows that the restored AtHPPD-HPPA-Fe(II) complex is still nonreactive toward the bound dioxygen. QM/MM and QM calculations reveal that the HPPA resists the electrophilic attacking of the bound dioxygen by the trim of its phenyl ring, and the residue Phe381 plays a key role in orienting the phenyl ring. Kinetic study on the F381A mutant reveals that the HPPD-HPPA complex observed in the crystal structure should be an intermediate of the substrate transportation instead of the pre-reactive complex. More importantly, the binding mode of the HPPA in this complex is shared with several well-known HPPD inhibitors, suggesting that these inhibitors resist the association of dioxygen (and exert their inhibitory roles) in the same way as the HPPA. The present study provides insights into the inhibition mechanism of HPPD inhibitors.
Toward a high added value compound 3, 4-dihydroxyphenylacetic acid by electrochemical conversion of phenylacetic acid
Trabelsi, Souhel Kallel,Dridi Gargouri, Olfa,Gargouri, Boutheina,Abdelhèdi, Ridha,Bouaziz, Mohamed
, p. 370 - 376 (2015/05/27)
Abstract The development of the effective procedure to recover the potentially high-added-value phenolic compound, 3,4-dihydroxyphenylacetic acid (3,4-DHPAA) was investigated using electrochemical conversion of phenylacetic acid (PAA). The proposed mechanism is based on the hypothesis of two-electron oxidation of PAA molecule leading to 3-hydroxyphenyl acetic acid. The latter underwent a second bi-electronic transfer by means of a radical cation, thus leading to the formation of the 2,5 dihydroxyphenylacetic (2,5-DHPAA) acid and 3,4-DHPAA as major products. The 3,4-DHPAA was synthesized by anodic oxidation of PAA at lead dioxide electrode and identified by cyclic voltammetry and spectrophotometry UV-visible. It was also confirmed by mass spectrophotometry using LC-MS/MS apparatus. According to their voltammetric behavior during electrolysis, the oxidation potential of 3,4-DHPAA was lower than that of PAA. The antioxidant activity was measured by DPPH assay, showing that the strongest antiradical activity was detected when the 3,4-DHPAA concentration was higher during electrolysis experiments.
Phytotoxic effects of selected N-benzyl-benzoylhydroxamic acid metallo-oxygenase inhibitors: Investigation into mechanism of action
Sergeant, Martin J.,Harrison, Peter J.,Jenkins, Robert,Moran, Graham R.,Bugg, Timothy D. H.,Thompson, Andrew J.
, p. 3461 - 3465 (2013/11/06)
Treatment of Arabidopsis thaliana with 100 μM hydroxamic acids F1 and F2, found previously to inhibit carotenoid cleavage dioxygenase enzyme CCD1, was found to cause chlorophyll bleaching and phytotoxicity. A further set of hydroxamic acid analogues was synthesised, and these compounds were found to be phytotoxic towards A. thaliana at 16-400 μM, and to show some phytoxicity towards broad-leaved weeds C. album and S. media at 100 μM. Compound F1 was found to inhibit p-hydroxy-phenylpyruvate dioxygenase (HPPD), a known herbicide target (IC50 30 μM), but compounds F5 and F8 showed no inhibition of HPPD, despite F8 showing higher levels of phytotoxicity. Plants grown in the presence of F1 or F5 that were treated with 50 μM homogentisic acid showed partial recovery of growth, indicating some inhibition of HPPD in planta. These are the first hydroxamic acid inhibitors reported for HPPD, but the results indicate that inhibition of HPPD is only partly responsible for the observed phytotoxicity, and that another unknown metalloenzyme is also targeted by these compounds.
