| | 1 | Author
| KenjiM. Atsui, Hiroyuki Shinta, H. Irom, Itsu Toyota, Tadahiko Kajiwara, AkikazuH. Atanaka | Requires 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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| default:Reihe_C/47/ZNC-1992-47c-0085.pdf | | | | Identifier
| ZNC-1992-47c-0085 | | | | Volume
| 47 | |
| 2 | Author
| A. Kikazu, H. Atanaka, Tadahiko Kajiwara, KenjiM. Atsui, AkiraK. Itam Ura | Requires 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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| default:Reihe_C/47/ZNC-1992-47c-0369.pdf | | | | Identifier
| ZNC-1992-47c-0369 | | | | Volume
| 47 | |
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