tailieunhanh - Kinetic studies with crude tomato lipoxygenase

Crude tomato lipoxygenase (LOX) from ripe Florida47 tomatoes was used in this study. Extracted crude LOX was assayed spectrophotometrically. The effects of different buffers and pHs, substrate preparations, temperature and tissue location on LOX activity were evaluated. | Turk J Agric For 25 (2001) 291-296 © TÜB‹TAK Kinetic Studies With Crude Tomato Lipoxygenase Emin YILMAZ Çanakkale Onsekiz Mart Üniversitesi, Mühendislik-Mimarl›k Fakültesi, G›da Mühendisli¤i Bölümü, 17100, Çanakkale - TURKEY Received: Abstract: Crude tomato lipoxygenase (LOX) from ripe Florida47 tomatoes was used in this study. Extracted crude LOX was assayed spectrophotometrically. The effects of different buffers and pHs, substrate preparations, temperature and tissue location on LOX activity were evaluated. The enzyme was most active with MES buffer at a pH of and a temperature of 25ºC. The best substrate was the first preparation with linoleic acid/Tween 20 at a ratio of 1:. The kinetic parameters determined under the best conditions were a Km of mM and a Vmax of mM/min. The enzyme was heat labile, and most activity was located in the fruit pericarp tissue. These results may help in employing crude tomato LOX as a biotechnological source. Key Words: tomato, lipoxygenase, crude, kinetics, substrate Ham domates Lipoksigenaz›yla Kinetik Çal›flmalar Özet: Bu çal›flmada, Florida47 domateslerinden elde edilen ham domates lipoksijenaz› (LOX) kullan›lm›flt›r. LOX ölçümü spektrofotometrik metotla yap›lm›flt›r. Fakl› tampon ve pH’lar›n, haz›rlanm›fl substratlar›n, s›cakl›¤›n ve doku bölgesinin LOX aktivitesi üzerine etkisi belirlenmifltir. Enzim, pH’s› olan MES tamponu ile 25 ºC’de en yüksek aktiviteyi göstermifltir. En iyi substrat, linoleik asit / Tween 20 oran›n›n 1: oldu¤u birinci preperatt›r. En iyi koflullarda ölçülen kinetik parametreler, mM Km ve mM / min Vmax de¤erlerini vermifltir. S›ca¤a dayan›kl› olmayan enzim aktivitesinin ço¤u meyvenin perikarp dokusunda toplanm›flt›r. Bu çal›flman›n sonuçlar›, domates LOX’ unun biyoteknoloji alan›nda kullan›m›na yard›mc› olabilir. Anahtar Sözcükler: domates, lipoksigenaz, ham, kinetik, substrat Introduction Lipoxygenase (LOX, EC , .