This study was conducted to evaluate antioxidant enzyme activities in four caprifig varieties under drought stress and subsequent rewatering in order to screen drought tolerance. Leaf relative water content and membrane stability index significantly reduced under drought stress. ‘Shah Anjir’ and ‘Khormaei’ were able to preserve the highest relative water content and membrane stability index lev...

Levels of reactive oxygen species (ROS) are tightly regulated in mammalian cells. A variety of enzymes produce ROS, including NAD(P)H oxidase, xanthine oxidase, glucose oxidase, myeloperoxidase, the family of nitric oxide synthases, and mitochondrial enzymes.1–4 Low levels of ROS such as superoxide or hydrogen peroxide regulate highly specific targets.5,6 In the cardiovascular system, for examp...

Genome analyses revealed in various basidiomycetes the existence of multiple genes for blue multi-copper oxidases (MCOs). Whole genomes are now available from saprotrophs, white rot and brown rot species, plant and animal pathogens and ectomycorrhizal species. Total numbers (from 1 to 17) and types of mco genes differ between analyzed species with no easy to recognize connection of gene distrib...

Glutathione (GSH) dependent protection against oxidative damage of human red cell membrane was examined. An artificial system was used in which chloroform/methanolextracted red cell lipids. in the form of liposomes. were subjected to attack by a peroxidation system consisting of ascorbate-Fe3 . Human erythrocytes contained a nondialyzable factor. completely inactivated by heating in a boiling w...

Vascular leakage in multiple organs is a characteristic pathological change in sepsis. Our recent study revealed that ascorbate protects endothelial barrier function in microvascular endothelial cell monolayers through inhibiting serine/threonine protein phosphatase 2A (PP2A) activation (Han M, Pendem S, Teh SL, Sukumaran DK, Wu F, Wilson JX. Free Radic Biol Med 48: 128-135, 2010). The present ...

Cytochrome c oxidase (CCO) is the Cu-dependent, terminal respiratory complex of the mitochondrial electron transport chain. Inhibition of CCO can promote oxidative stress by increasing mitochondrial production of reactive oxygen species (ROS). Because mitochondria have an important role in apoptosis as both a target and source for ROS, enhanced ROS production resulting from inhibition of CCO by...

We describe a specific enzymatic spectrophotometric method for ascorbic acid in serum or plasma. Samples are analyzed indirectly by measuring the absorbance at 593 nm of a reaction product, a complex of ferrous ion and 2,4,6-tris(2-pyridyl)-s-triazine (Fe2+-TPTZ). This product is formed by reduction of the corresponding ferric ion complex (Fe3+-TPTZ), which is nonspecifically reduced by various...

Certain diagnostic kits that measure serum urate by the Barham and Trinder principle of enzymic liberation of oxygen and its combination with chromogens can give results for urate in fresh serum that are approximately 20% lower than results from serum stored at ambient temperature for 72 h. In fresh serum, antioxidants compete with chromogen for liberated peroxyl-oxygen. We postulate that durin...

Ethylene is a plant hormone important in many aspects of plant growth and development such as germination, fruit ripening, and senescence. 1-Aminocyclopropane-1-carboxylic acid (ACC) oxidase (ACCO), an O2-activating ascorbate-dependent nonheme iron enzyme, catalyzes the last step in ethylene biosynthesis. The O2 activation process by ACCO was investigated using steady-state kinetics, solvent is...