1,721,019 research outputs found
Decrease of cytosolic ATP content under hyperosmotic stress in durum wheat seedlings as evaluated by a new simple method
No full textTHE REACTION BETWEEN SOYBEAN LIPOXYGENASE–1 ISOENZYME AND FLUORESCEINE AS A NOVEL TOOL TO ASSESS ANTIOXIDANT ACTIVITY IN FOODS
No full textTHE REACTION BETWEEN SOYBEAN LIPOXYGENASE–1 ISOENZYME AND FLUORESCEINE AS A NOVEL TOOL TO ASSESS ANTIOXIDANT ACTIVITY IN FOODS
No full textPlant mitochondrial potassium channel or channels?
No full textInvited Expert Commentary. Free online
https://www.novapublishers.com/catalog/index.php?cPath=23_29&seriesp=Botanical+Research+and+Practices&osCsid=acf7a7149fc438ae67601d794d006ff
THE NEW LOX/RNO METHOD ALLOWS MEASUREMENT OF HIGH ANTIOXIDANT ACTIVITY OF FREE AND BOUND PHENOLS IN SEEDS OF CEREAL SPECIES
No full textEvaluation of synergistic interactions of antioxidants from plant foods by a new method using soybean lipoxygenase
No full textA proper evaluation of synergism among antioxidants remains so far rather difficult to obtain. We recently reported
that a new method for antioxidant activity measurement, based on the secondary reaction of soybean lipoxygenase
(LOX)-1 isoenzyme with 4-nitroso-N,N-dimethylaniline (RNO), so-called LOX/RNO method, may assess very well
the synergism among antioxidants from durum wheat whole semolina. To evaluate whether this behaviour is generalizable
to different food matrices, herein, antioxidants from other very different sources were analysed. For this purpose,
antioxidant activity of food-grade preparations enriched in catechins, quercetin, resveratrol, tyrosol/hydroxytyrosol
and lycopene was evaluated by the LOX/RNO method in comparison with the Trolox equivalent antioxidant ca pacity
(TEAC) assay. The antioxidant activity values obtained by LOX/RNO method were 2–90-times higher than those
obtained by the TEAC protocol, depending on the tested antioxidant. Synergism was evaluated by comparing antioxidant
activity of the mixture of compounds (AAmix) with the sum of antioxidant activity values of individual compounds
(AAsum). The LOX/RNO method revealed a strong synergism, being AAmix 5.69 ± 0.31 times higher than AAsum (statistically
significant, p < 0.001), while the TEAC method showed a synergistic increase of only 0.31 ± 0.04 (statistically
significant, p < 0.01). These findings suggest that the LOX/RNO method is able to assess very well the synergism in
various food samples
The existence of sirtuin activity in purified durum wheat (Triticum durum Desf.) mitochondria
No full textAn Improved Spectrophotometric Phospholipase A2 Assay Using 1-Palmitoyl-2-Linoleoyl-sn-Glycero-3- Phosphatidylcholine as Substrate and Lipoxygenase as Coupled Enzyme
No full textAn improved spectrophotometric assay of phospholipase A2 (PLA2) activity based on the coupled PLA2/lipoxygenase (LOX) reactions using 1-palmitoyl-2-linoleoyl-sn-glycero-3- phosphatidylcholine (PCLIN) as substrate is reported. The PLA2- mediated release of free linoleate is continuously monitored by following the absorbance increase at 234 nm caused by its conversion into the conjugated diene hydroperoxide catalyzed by the coupled soybean LOX-1 reaction. The new protocol includes the use of Tween 20 (3 μL/mmol phospholipid) as surfactant and of ethanol (15 μL/mL reaction mixture), that ensure clearness of reaction mixture and linear increase of absorbance in the course of reaction. This method was tested on a purified secretory PLA2 from honey bee venom (HBV-PLA2). The enzyme did not discriminate among PCLIN, phosphatidylcholine, and phosphatidylethanolamine, but showed the highest rate using 1,2- dilinoleoyl-sn-glycero-3-phosphatidylcholine (PCDILIN). Nevertheless, the use of PCDILIN is not recommended, as it may induce an overestimation of enzyme activity, because not only the free linoleate, but also the reaction product 1-linoleoyl-lysophosphatidylcholine, are known to be oxidized by LOX. HBV-PLA2 showed maximal activity at pH 9.0, hyperbolic kinetics (Km, 74.22.9 μM; Vmax, 8277 μmol/min/mg protein) and competitive inhibition (Ki about 5 μM) by palmityl trifluoromethyl ketone, a classical PLA2 inhibitor. Interestingly, the HBV-PLA2/soybean LOX-1 coupled reactions also allow an accurate assay of PCLIN concentration. In the whole, these results demonstrate that this improved PLA2/LOX assay allows a very accurate, simple, and rapid measurement of enzyme activity and substrate concentration
Improvement of the oxygen radical absorbance capacity (ORAC) assay to assess antioxidant activity of phenols and plasma by using lipoxygenase reaction as a radical generator
No full textIdentificazione di un canale mitocondriale del potassio come possibile strumento per migliorare la resistenza agli stress abiotici in frumento duro.
No full text- …
