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'Lipoxygenase' in keywords Facet   Publication Year 1992  [X]
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1Author    KenjiM. Atsui, Hiroyuki Shinta, H. Irom, Itsu Toyota, Tadahiko Kajiwara, AkikazuH. AtanakaRequires cookie*
 Title    Comparison of the Substrate Specificities of Lipoxygenases Purified from Soybean Seed, Wheat Seed, and Cucumber Cotyledons  
 Abstract    Lipoxygenases were highly purified from soybean seed, wheat seed and cucumber cotyle­ dons. Substrate specificities o f these lipoxygenases were studied by using an entire series o f (co6Z ,co9Z)-C 13~C24-dienoic acids as synthetic substrate analogues. Soybean lipoxygenase-1 and cucumber lipoxygenase showed broad specificities for these substrates while wheat lipoxygenase showed narrow specificities. Position o f dioxygenation to each substrate was an­ alyzed by high performance liquid chromatography. W ith soybean lipoxygenase-1 elongation o f the distance between the terminal carboxyl group and the site o f hydrogen removal in a substrate decreased the positional specificity o f dioxygenation, while, with cucumber lipoxy­ genase, shortening the distance decreased the specificity. It was suggested that cucumber lipoxygenase and soybean lipoxygenase-1 recognized the terminal carboxyl group o f a sub­ strate to arrange it only in one orientation at the reaction center. In case o f wheat lipoxygen­ ase, recognition o f the carboxyl group was thought to have crucial and essential role to secure the activity. 
  Reference    Z. Naturforsch. 47c, 85—8 (1992); received M ay 8/A ugust 27 1991 
  Published    1992 
  Keywords    Lipoxygenase, Cucumber Cotyledons, Soybean Seed, W heat Seed, Substrate Specificity 
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 TEI-XML for    default:Reihe_C/47/ZNC-1992-47c-0085.pdf 
 Identifier    ZNC-1992-47c-0085 
 Volume    47 
2Author    A. Kikazu, H. Atanaka, Tadahiko Kajiwara, KenjiM. Atsui, AkiraK. Itam UraRequires cookie*
 Title    Expression of Lipoxygenase and Hydroperoxide Lyase Activities in Tomato Fruits  
 Abstract    The distribution (or locarization) o f lipoxygenase (LOX) and hydroperoxide lyase (HPO lyase) activities in ripening and ripe tomato fruits was investigated. The highest LOX activity existed between skin and outer flesh o f tom ato fruits. HPO lyase showed no tissue specificity. LOX specifically formed linoleic acid 9-£',Z-hydroperoxide (9-.E,Z-HPO) from linoleic acid (LA), whereas HPO lyase specifically cleaved 13-Z.^-H PO . A lthough a low level (0.36 ± 0.069 nm ol/g fr. wt.) o f hexanal was detected in the intact tom ato fruit, HPOs were not detected. When a tom ato fruit was injured by cutting it into 8 fragments and incubated at 25 °C, hexanal increased to 1.642 nmol/g fr.wt. by 30 min. By hom ogenizing at pH 6.3, hex-anal increased to 21.1 nm ol/g fr.wt. during a 30 min incubation. U V irradiation o f tom ato fruits also increased the formation o f hexanal. From these results, LOX and HPO lyase are considered to exist as latent forms and to begin the expression o f the activity upon injury. 
  Reference    Z. Naturforsch. 47c, 369—3 (1992); received M ay 27 1991/March 4 1992 
  Published    1992 
  Keywords    H istological Localization, Hydroperoxide Lyase, Injury, Lipoxygenase, T om ato Fruit 
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 TEI-XML for    default:Reihe_C/47/ZNC-1992-47c-0369.pdf 
 Identifier    ZNC-1992-47c-0369 
 Volume    47