Alteration of enzyme activities and kinetic properties of GST and NQO1 with naturally occurring phenolic compounds
Küçük Resim Yok
Tarih
2015
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
WALTER DE GRUYTER GMBH
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
Objective: Glutathione S-transferase (GST) and NAD(P)H:quinine oxidoreductase 1 (NQO1) are the enzymes important in cytoprotection and bioactivation of chemicals. This study has addressed effects of polyphenolic compounds; ellagic acid, quercetin, naringenin, resveratrol, rutin and hesperidin on rabbit liver GST and NQO1 enzyme activities. Methods: Cytosolic fractions were obtained from homogenized liver tissues of rabbit by differential centrifugation. After calculating IC50 values of individual enzymes for phenolic compounds, both Lineweaver-Burk and Dixon plots were drawn to determine the effect of phenolics on enzyme activity. Michaelis-Menten constant (K-m), maximum velocity (V-max), and inhibition constant (K-i) were calculated from Lineweaver-Burk and Dixon plots, respectively. Results: Resveratrol was found to be the most potent inhibitor for rabbit hepatic cytosolic GST activity with 75.9 +/- 2.06 mu M IC50 value while naringenin was the least potent one with IC50 value of 260 +/- 1.92 mu M. Hesperidin and quercetin were found to be the most and least potent inhibitors for NQO1 enzyme activity with IC50 values of 2.7 +/- 0.85 mu M and 13.8 +/- 0.91 mu M, respectively. Resveratrol and naringenin inhibited GST activity noncompetitively and mixed type with K-i of 6.2 mu M and 245 mu M, respectively; while both hesperidin with 0.64 mu M K-i value and quercetin with 3.5 mu M K-i value inhibited NQO1 activity in a competitive manner. Conclusion: These results indicate that phenolic compounds may modulate Phase II enzyme, GST and NQO1. Moreover, they can influence the metabolic activation of xenobiotic and toxic compounds metabolized by this enzyme.
Açıklama
Anahtar Kelimeler
GST, NQO1, polyphenols, inhibition kinetic, IC50
Kaynak
TURKISH JOURNAL OF BIOCHEMISTRY-TURK BIYOKIMYA DERGISI
WoS Q Değeri
Q4
Scopus Q Değeri
Q4
Cilt
40
Sayı
3
