1,721,010 research outputs found
Hexokinase inactivation induced by ascorbic acid/Fe(II) in rabbit erythrocytes is independent of glutathione-reductive processes and appears to be mediated by dehydroascorbic acid.
No full textRecent studies performed in our laboratory demonstrated that rabbit red blood cell hexokinase was remarkably inhibited by the cocktail ascorbic acid/Fe(II) (Stocchi et al., 1994, Arch. Biochem. Biophys. 311, 160-167) and that the formation of dehydroascorbic acid was a key event in this process (Fiorani et al., 1996, Arch. Biochem. Biophys, 334, 357-361). The present study was undertaken to determine the final hexokinase-inactivating species using cell-free extract as a model. Our results demonstrate superimposable kinetics of hexokinase decay promoted by either ascorbic acid/Fe(II) or dehydroascorbic acid in erythrocyte lysates in which the reduced glutathione (GSH) levels were variously manipulated. In particular, neither removal nor addition of this tripeptide was able to significantly alter the rate or extent of hexokinase inhibition. Thus, GSH-reductive processes are dispensable events in the process of hexokinase inhibition promoted by ascorbic acid/Fe(II) in red blood cells. As a consequence, dehydroascorbic acid appears to be the species which directly inhibits hexokinase. This inference is further supported by the observation that addition of dehydroascorbic acid to the purified enzyme leads to a remarkable inhibition in its activity
Effect of storage on biochemical and microbiological parametersof edible truffle species
Full text linkThe effects of different storage treatments on the most common edible truffle species, such as Tuber magnatum and Tuber borchii (white truffles), Tuber melanosporum and Tuber aestivum (black truffles), were analysed. Biochemical and microbiological profiles were monitored, in order to evaluate possible alterations during truffle preservation. After harvesting, some fresh samples were kept at 4 C for 30 days, other samples were frozen at 20 C for one month, thawed and preserved at 4 C; the remainder were autoclaved.
The biochemical parameters studied were sugar and protein content, the activity of some enzymes involved in the central metabolism
of the fungi and the electrophoretic pattern of soluble proteins. Total mesophilic bacteria were also counted. The results obtained showed
that the storage at 4 C is the treatment that best preserves the biochemical and microbiological characteristics of fresh truffles. Black
truffles were more resistant to biochemical spoilage than the white ones, while T. magnatum was the most resistant to microbial spoilage
Biosorption of heavy metals in the ectomycorrhizal fungus Tuber borchii: a preliminary molecular approach
No full textA high concentration of glucose inhibits Tuber borchii mycelium growth: a biochemical investigation
No full textEffect of storage on biochemical and microbiological parameters of edible truffle species.
No full textPossible involvement of Pseudomonas fluorescens and Bacillaceae in structural modifications of Tuber borchii fruit body.
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Carbohydrate and nitrogen metabolism in the ectomycorrhizal fungus Tuber borchii Vittad.
No full textNew evidence for bacterial diversity in the ascoma of the ectomycorrhizal fungus Tuber borchii Vittad.
No full textCharacterization and mRNA expression profile of the TbNre1 gene of the ectomycorrhizal fungus Tuber borchii.
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