Oxidation of ascorbic acid by lipoxygenase: Effect of selected chemicals

Cyclodextrins as Secondary Antioxidants: Synergism with Ascorbic Acid

“…These two LOXcatalyzed reactions are of interest to food scientists, both because of their role in the genesis of volatile flavor and aroma compounds in plant products and because of their ability to form free radicals which can then attack other constituents, such as proteins, colors, phenolics, and vitamins. In fact, Roy and Kulkarni (1996) have recently described the co-oxidation of ascorbic acid with linoleic acid.…”

Cyclodextrins as Secondary Antioxidants: Synergism with Ascorbic Acid

“…These two LOXcatalyzed reactions are of interest to food scientists, both because of their role in the genesis of volatile flavor and aroma compounds in plant products and because of their ability to form free radicals which can then attack other constituents, such as proteins, colors, phenolics, and vitamins. In fact, Roy and Kulkarni (1996) have recently described the co-oxidation of ascorbic acid with linoleic acid.…”

N-demethylation of phenothiazines by lipoxygenase from soybean and human term placenta in the presence of hydrogen peroxide

“…During this one electron transfer process, the reducing agent is expected to be oxidized to a free radical species. Earlier we reported that, in the absence of any oxidizable xenobiotic, both ascorbate [40] and GSH [41] are oxidized to the corresponding free radical species by SLO when reaction media are supplemented with appropriate polyunsaturated fatty acids. However, we strongly believe that the observed inhibition of formaldehyde accumulation (Table I) is mainly due to thiol pumping and not solely due to substrate competition, since both ascorbic acid and GSH are only minimally oxidized, if any, in the presence of H 2 O 2 (unpublished observations).…”

Isolation and some properties of dioxygenase and co-oxidase activities of adult human liver cytosolic lipoxygenase

“…(2) The fact that linoleic acid can only be used as a substrate by LO also eliminates the role played by prostaglandin synthetase, if any, in the co-oxidation of xenobiotics reported here. (3) Several previous studies have pointed out that as compared to arachidonate, the co-oxidation of xenobiotics, in general, is more efficiently coupled with the linoleate oxidation by many LOs (2)(3)(4)(32)(33)(34)(41)(42)(43)(44)47). (4) Arachidonic acid is known to undergo multiple side reactions via LO pathway.…”

Cyclodextrins as Secondary Antioxidants: Synergism with Ascorbic Acid

“…These two LOXcatalyzed reactions are of interest to food scientists, both because of their role in the genesis of volatile flavor and aroma compounds in plant products and because of their ability to form free radicals which can then attack other constituents, such as proteins, colors, phenolics, and vitamins. In fact, Roy and Kulkarni (1996) have recently described the co-oxidation of ascorbic acid with linoleic acid.…”

N-demethylation of phenothiazines by lipoxygenase from soybean and human term placenta in the presence of hydrogen peroxide

“…During this one electron transfer process, the reducing agent is expected to be oxidized to a free radical species. Earlier we reported that, in the absence of any oxidizable xenobiotic, both ascorbate [40] and GSH [41] are oxidized to the corresponding free radical species by SLO when reaction media are supplemented with appropriate polyunsaturated fatty acids. However, we strongly believe that the observed inhibition of formaldehyde accumulation (Table I) is mainly due to thiol pumping and not solely due to substrate competition, since both ascorbic acid and GSH are only minimally oxidized, if any, in the presence of H 2 O 2 (unpublished observations).…”

Isolation and some properties of dioxygenase and co-oxidase activities of adult human liver cytosolic lipoxygenase

“…(2) The fact that linoleic acid can only be used as a substrate by LO also eliminates the role played by prostaglandin synthetase, if any, in the co-oxidation of xenobiotics reported here. (3) Several previous studies have pointed out that as compared to arachidonate, the co-oxidation of xenobiotics, in general, is more efficiently coupled with the linoleate oxidation by many LOs (2)(3)(4)(32)(33)(34)(41)(42)(43)(44)47). (4) Arachidonic acid is known to undergo multiple side reactions via LO pathway.…”

Cyclodextrins as Secondary Antioxidants: Synergism with Ascorbic Acid

“…These two LOXcatalyzed reactions are of interest to food scientists, both because of their role in the genesis of volatile flavor and aroma compounds in plant products and because of their ability to form free radicals which can then attack other constituents, such as proteins, colors, phenolics, and vitamins. In fact, Roy and Kulkarni (1996) have recently described the co-oxidation of ascorbic acid with linoleic acid.…”

N-demethylation of phenothiazines by lipoxygenase from soybean and human term placenta in the presence of hydrogen peroxide

“…During this one electron transfer process, the reducing agent is expected to be oxidized to a free radical species. Earlier we reported that, in the absence of any oxidizable xenobiotic, both ascorbate [40] and GSH [41] are oxidized to the corresponding free radical species by SLO when reaction media are supplemented with appropriate polyunsaturated fatty acids. However, we strongly believe that the observed inhibition of formaldehyde accumulation (Table I) is mainly due to thiol pumping and not solely due to substrate competition, since both ascorbic acid and GSH are only minimally oxidized, if any, in the presence of H 2 O 2 (unpublished observations).…”

Isolation and some properties of dioxygenase and co-oxidase activities of adult human liver cytosolic lipoxygenase

“…(2) The fact that linoleic acid can only be used as a substrate by LO also eliminates the role played by prostaglandin synthetase, if any, in the co-oxidation of xenobiotics reported here. (3) Several previous studies have pointed out that as compared to arachidonate, the co-oxidation of xenobiotics, in general, is more efficiently coupled with the linoleate oxidation by many LOs (2)(3)(4)(32)(33)(34)(41)(42)(43)(44)47). (4) Arachidonic acid is known to undergo multiple side reactions via LO pathway.…”