Induction of cytochrome p450 1A1 and 1B1 by photooxidized tryptophan in transformed human keratinocytes.
L-Tryptophan was oxidized by UVA, UVB, or UVC irradiation and the effect of oxidized tryptophan (OT) was investigated for its ability to induce CYP1A1 and 1B1 in a human keratinocyte cell line (HaCat). The results obtained demonstrate that tryptophan oxidized by UVA, UVB, or UVC produced photoproducts which caused a significant induction of 7-ethoxyresorufin O-deethylase (EROD) activity in HaCat cells. The induction of EROD activity by UVB-OT was studied in greater detail. The results demonstrate that induction of EROD activity by UVB-OT was dose- and time-dependent. Results with immunoblot analyses showed that administration of UVB-OT, but not unoxidized tryptophan, caused a marked induction of CYP1A1 and 1B1 proteins in HaCat cells.
Sindhu
Ram K
RK
Department of Pathology, College of Medicine, University of California, Irvine, CA 92697-4800, USA. rksindhu@uci.edu
Wagner
Frances E
FE
Kikkawa
Yutaka
Y
D001189:Aryl Hydrocarbon Hydroxylases / Q000096:biosynthesis*; D002461:Cell Line, Transformed; D019363:Cytochrome P-450 CYP1A1 / Q000096:biosynthesis*; D065633:Cytochrome P-450 CYP1B1; D004790:Enzyme Induction / Q000187:drug effects; D006801:Humans; D015603:Keratinocytes / Q000187:drug effects* / Q000201:enzymology*; D010084:Oxidation-Reduction; D010777:Photochemistry; D014364:Tryptophan / Q000494:pharmacology* / Q000528:radiation effects*; D014466:Ultraviolet Rays / Q000009:adverse effects
D014364:Tryptophan; D001189:Aryl Hydrocarbon Hydroxylases; C585496:CYP1B1 protein, human; D019363:Cytochrome P-450 CYP1A1; D065633:Cytochrome P-450 CYP1B1