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Literature summary for 4.2.1.92 extracted from

  • Cristea, M.; Oliw, E.H.
    A G316A mutation of manganese lipoxygenase augments hydroperoxide isomerase activity: mechanism of biosynthesis of epoxyalcohols (2006), J. Biol. Chem., 281, 17612-17623.
    View publication on PubMed

Cloned(Commentary)

Cloned (Comment) Organism
expression in Pichia pastoris Gaeumannomyces graminis

Protein Variants

Protein Variants Comment Organism
G316A the G316A mutant increases the oxygenation at the n-8 carbon of 17:3n-3 and at the n-10 carbon of the C17 and C18 fatty acids (from 1–2% to 7–11%). The most striking effect of the G316A mutant is a 2-, 7-, and 15-fold increase in transformation of the n-6 hydroperoxides of 19:3n-3, 18:3n-3, and 17:3n-3, respectively, to keto fatty acids and epoxyalcohols. G316A mutant augments the hydroperoxide isomerase activity by positioning the hydroperoxy group at the n-6 carbon of n-3 fatty acids closer to the reduced catalytic metal Gaeumannomyces graminis
G316S inactive mutant enzyme Gaeumannomyces graminis
G316T inactive mutant enzyme Gaeumannomyces graminis
G316V inactivfe mutant enzyme Gaeumannomyces graminis

Organism

Organism UniProt Comment Textmining
Gaeumannomyces graminis Q8X151 var. avenae
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Purification (Commentary)

Purification (Comment) Organism
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Gaeumannomyces graminis

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
(13R)-hydroperoxylinolenic acid the G316A mutant converts (13R)-hydroperoxylinolenic acid to 13-ketolinolenic acid (with an apparent Km of 0.01 mM) and to epoxyalcohols viz. erythro- and threo-11-hydroxy-(12R,13R)-epoxy-(9Z,15Z)-octadecadienoic acids and one of the corresponding cis-epoxides as major products Gaeumannomyces graminis 13-ketolinolenic acid + threo-11-hydroxy-(12R,13R)-epoxy-(9Z,15Z)-octadecadienoic acid + erythro-11-hydroxy-(12R,13R)-epoxy-(9Z,15Z)-octadecadienoic acid
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heptadecatrienoic acid the G316A mutant transforms 17:3n-3 to both 12-hydroperoxyheptadecatrienoic acid (about 93%) and 10-hydroperoxyheptadecatrienoic acid (7%) Gaeumannomyces graminis 12-hydroperoxyheptadecatrienoic acid + (8Z,10S,11Z,14Z)-10-hydroperoxyheptadeca-8,11,14-trienoic acid
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linoleic acid Mn-LO G316A metabolizeS 18:2n-6 to (11S)-hydroperoxyoctadecadienoic acid and (13R)-hydroperoxyoctadecadienoic acid in approximately the same relative amounts as the native enzyme, and (13R)-hydroperoxyoctadecadienoic acid accumulates as the end product Gaeumannomyces graminis ?
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linolenic acid Mn-LO G316A metabolizes 18:3n-3 to (13R)-hydroperoxyoctadecatrienoic acid and (11S)-hydroperoxyoctadecatrienoic acid Gaeumannomyces graminis (13R)-hydroperoxyoctadecatrienoic acid + (11S)-hydroperoxyoctadecatrienoic acid
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additional information catalytic properties of Mn-LO and the G316A mutant with heptadecatrienic acid, 18:2n-6, octadecatrienoic acid, and nonadecatrienoic acid as substrates: increasing the fatty acid chain length from C17 to C19 shifts the oxygenation by Mn-LO from the n-6 toward the n-8 carbon. The G316A mutant increases the oxygenation at the n-8 carbon of 17:3n-3 and at the n-10 carbon of the C17 and C18 fatty acids (from 1–2% to 7–11%). The most striking effect of the G316A mutant is a 2fold, 7fold, and 15fold increase in transformation of the n-6 hydroperoxides of 19:3n-3, 18:3n-3, and 17:3n-3, respectively, to keto fatty acids and epoxyalcohols. The n-3 double bond is essential. Both oxygen atoms are retained in the epoxyalcohols. (R)-Hydroperoxides at n-6 of C17:3, 18:3, and 19:3 are transformed 5times faster than (S)-stereoisomers Gaeumannomyces graminis ?
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Synonyms

Synonyms Comment Organism
Mn-LO
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Gaeumannomyces graminis