The thermostabilization of some enzymes by amidination with dimethylsuberimidate was surveyed. In the enzymes investigated, a moderate increase of thermostability in glucose oxidase and invertase, and prominent increase in lactate dehydrogenase, alcohol dehydrogenase and ascorbate oxidase were observed. The increase of thermostability by amidination was suggesting the synergism of the enhanceme...

trehalose is an important disaccharide signal metabolite in plants which is involved in various aspects of plant function such as response to stress, photosynthesis and carbon allocation and partitioning. a mutant of arabidopsis lacking trehalose-6-phosphate synthase activity (tps1) accumulates ascorbate. exogenous ascorbate application ameliorates trehalose induced growth inhibition of wild ty...

cision is not better than 2% of the maximum concentration of each concentration range. This means that an error of 0.02 mg/L S in the 0-1 mg/L S range corresponds to an error of 1 mg/L S in the 0-50 mg/L S range. For optimum precision, the response of the analyzer should be kept large by selecting the syringe size according to the sulfur content of the analyte and maintaining a reasonably rapid...

The electrochemistry of some copper-containing proteins and enzymes, viz. azurin, galactose oxidase, tyrosinase (catechol oxidase), and the "blue" multicopper oxidases (ascorbate oxidase, bilirubin oxidase, ceruloplasmin, laccase) is reviewed and discussed in conjunction with their basic biochemical and structural characteristics. It is shown that long-range electron transfer between these enzy...

We describe a rapid kinetic glucose oxidase (EC 1.1.3.4) procedure for quantifying glucose. Glucose oxidase concentration was reduced from the more usual 20 kU/L to 4 kU/L, and pH was reduced from 7.0 to 6.6. Potassium ferrocyanide (20 mumol/L) and ascorbate oxidase (1 kU/L) were incorporated in the procedure. The assay results vary linearly with glucose concentration from 0 to 50 mmol/L and ar...

Deamination is one step in the metabolism of amino acids. This process is catalyzed by the Dand L-amino acid oxidases. It is known that various endocrine secretions will affect the rate of enzymatic reactions. The present communication presents data on the interrelation of amino acid concentration in the blood and the secretions of the hypophysis, adrenal, and thyroid on the rate of activity of...

introduction plant responses to environmental stress have a central role in agricultural production. responses results from events occurring at all levels of the organization, from biochemical reactions in cells to whole plant physiology. many plants are injured when exposed to low non-freezing temperatures. however, data on the effects of night temperatures are scarce. on the other hand, nitri...

1-Aminocyclopropane-1-carboxylic acid (ACC) oxidase (ACCO) catalyses the final step in ethylene biosynthesis converting ACC to ethylene, cyanide, CO2, dehydroascorbate and water with inputs of Fe(II), ascorbate, bicarbonate (as activators) and oxygen. Cyanide activates ACCO. A 'nest' comprising several positively charged amino acid residues from the C-terminal α-helix 11 along with Lys158 and A...