An isotopic study (2H and 18O) of the enzymic conversion of linoleic acid into colneleic acid with carbon chain fracture: the origin of shorter chain aldehydes
摘要:
Contrary to earlier reports, the divinyl 9-ether oxygen of coloneleic acid is shown by experiment with O-18(2) to originate from oxygen, not water. Using [9,10,12,13-H-2(4)]-9(S)-hydroperoxyoctadeca-10(E), 12(Z)-dienoic acid, made enzymically from synthetic [9,10,12,13-H-2(4)]linoleic acid, it is found that the distribution of deuterium as determined by NMR and mass spectrometry in the fractured carbon chain of colneleic acid formed by potato enzyme, is consistent with the intervention of an epoxycarbonium ion intermediate. Though divinyl acids such as colneleic and colnelenic acid give the expected shorter chain aldehydes on treatment with aqueous acid, it is likely that the latter are formed in most plants by trapping of a monovinyl oxonium ion rather than by rehydration of colneleic and colnelenic acid.
An isotopic study (2H and 18O) of the enzymic conversion of linoleic acid into colneleic acid with carbon chain fracture: the origin of shorter chain aldehydes
摘要:
Contrary to earlier reports, the divinyl 9-ether oxygen of coloneleic acid is shown by experiment with O-18(2) to originate from oxygen, not water. Using [9,10,12,13-H-2(4)]-9(S)-hydroperoxyoctadeca-10(E), 12(Z)-dienoic acid, made enzymically from synthetic [9,10,12,13-H-2(4)]linoleic acid, it is found that the distribution of deuterium as determined by NMR and mass spectrometry in the fractured carbon chain of colneleic acid formed by potato enzyme, is consistent with the intervention of an epoxycarbonium ion intermediate. Though divinyl acids such as colneleic and colnelenic acid give the expected shorter chain aldehydes on treatment with aqueous acid, it is likely that the latter are formed in most plants by trapping of a monovinyl oxonium ion rather than by rehydration of colneleic and colnelenic acid.
Synthesis of linoleic acids combinatorially labeled at the vinylic positions as substrates for lipoxygenases
作者:Matthew P. Meyer、Judith P. Klinman
DOI:10.1016/j.tetlet.2008.04.023
日期:2008.5
inflammation-related human diseases. Soybeanlipoxygenase-1 is the archetypical example of known lipoxygenases. Here we report the synthesis of linoleicacid and (11,11)-d2-linoleic acid which are combinatorially labeled at the vinylic positions (9, 10, 12, and 13). Combinatorial labeling schemes allow for the simultaneous determination of KIEs in enzymatic reactions using NMR. Substrates are, thus, available
An isotopic study (2H and 18O) of the enzymic conversion of linoleic acid into colneleic acid with carbon chain fracture: the origin of shorter chain aldehydes
作者:Leslie Crombie、David O. Morgan、Elisabeth H. Smith
DOI:10.1039/p19910000567
日期:——
Contrary to earlier reports, the divinyl 9-ether oxygen of coloneleic acid is shown by experiment with O-18(2) to originate from oxygen, not water. Using [9,10,12,13-H-2(4)]-9(S)-hydroperoxyoctadeca-10(E), 12(Z)-dienoic acid, made enzymically from synthetic [9,10,12,13-H-2(4)]linoleic acid, it is found that the distribution of deuterium as determined by NMR and mass spectrometry in the fractured carbon chain of colneleic acid formed by potato enzyme, is consistent with the intervention of an epoxycarbonium ion intermediate. Though divinyl acids such as colneleic and colnelenic acid give the expected shorter chain aldehydes on treatment with aqueous acid, it is likely that the latter are formed in most plants by trapping of a monovinyl oxonium ion rather than by rehydration of colneleic and colnelenic acid.