Effect of beta-carotene on the transformation of tyrosine by nitrogen dioxide and peroxynitrous acid.
In the NO2-exposure of tyrosine in 70% dioxane/phosphate buffer (pH 7.4), beta-carotene enhanced the degradation of tyrosine and/or 3-nitrotyrosine produced, whereas alpha-tocopherol and ascorbyl palmitate inhibited the transformation of tyrosine into 3-nitrotyrosine. Generation of certain active species in the interaction of beta-carotene with NO2 was suggested. Ascorbyl palmitate effectively and alpha-tocopherol slightly inhibited the transformation of tyrosine in the NO2-exposure in the presence of beta-carotene. In the reaction of tyrosine with ONOO-/ONOOH, beta-carotene enhanced the degradation of 3-nitrotyrosine produced suggesting generation of certain active species, whereas alpha-tocopherol and ascorbyl palmitate completely suppressed the transformation of tyrosine into 3-nitrotyrosine.
Kikugawa
K
K
School of Pharmacy, Tokyo University of Pharmacy and Life Science, Hachioji, Japan. kikugawa@ps.toyaku.ac.jp
Hiramoto
K
K
Tomiyama
S
S
Nakauchi
K
K
D001205:Ascorbic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D004146:Dioxanes; D004305:Dose-Response Relationship, Drug; D016166:Free Radical Scavengers / Q000494:pharmacology; D009585:Nitrogen Dioxide / Q000378:metabolism*; D009608:Nitrous Acid / Q000378:metabolism*; D030421:Peroxynitrous Acid; D013997:Time Factors; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology; D014810:Vitamin E / Q000494:pharmacology; D019207:beta Carotene / Q000378:metabolism / Q000494:pharmacology*
D004146:Dioxanes; D016166:Free Radical Scavengers; D019207:beta Carotene; D014810:Vitamin E; D030421:Peroxynitrous Acid; C002744:3-nitrotyrosine; D014443:Tyrosine; C007543:dityrosine; C025223:1,4-dioxane; D001205:Ascorbic Acid; C031226:6-O-palmitoylascorbic acid; D009585:Nitrogen Dioxide; D009608:Nitrous Acid