The enzymatic formation of the cyclodepsipeptide beauvericin was demonstrated in cell-free extracts from Beauveria bassiana. In analogy to the enniatin synthetase system formation of beauvericin is strictly dependent on the presence of the constituent amino and hydroxy acid, S-adenosylmethionine, and ATP/Mg2+. Synthesizing activity could be enriched about 12-fold by fractional ammonium sulfate ...

The ability of a number of mesoporous silica materials (SBA-15, SBA-3, and MCM-48) to immobilize polyphenol oxidase (PPO) at different pH has been tested. Pore size and volume are the structural characteristics with higher influence on the PPO immobilization. Mesoropous material SBA-15 adsorbs a larger quantity of PPO at pH 4.00 and offers an inhibition of enzymatic activity close the 50% in ap...

An amperometric cytochrome c-based electrode was developed and applied to the quantification of the scavenging capacity of antioxidants. The enzymatic biosensor was constructed by covalently immobilizing both cyt c and XOD on a mercaptoundecanoic acid/mercaptoundecanol mixed SAMmodified screen-printed gold electrode. The concentration which induces a 50% inhibition of the superoxide level (IC50...

The enzymatic degradation of CoA,’ giving rise to various fragments which are resynthesized to CoA by pigeon liver extracts, has been reported in a previous communication (1). Fractionation resulted in the isolation of the enzyme, pantetheine kinase, which converts pantetheine and ATP to 4’-phosphopantetheine (2). The present communication will describe the preparation and purification of the e...

Cell extracts from Micrococcus luteus release both free 3-methyladenine and free 7-methylguanine from alkylated DNA. The glycosylase activity responsible for the liberation of 7-methylguanine is not 3-methyladenine-DNA glycosylase, which, when purified, does not liberate it. Furthermore, the heat inactivation rates of the two enzymatic activities are different. The release of 7-methylguanine by...

Pseudomonas fluorescens NCIB 11764 was capable of utilizing cyanate (OCN-) as a sole nitrogen source for growth. Crude cell extracts from cells grown on cyanate, but not on ammonium sulfate, were induced for an enzyme catalyzing cyanate conversion to ammonia. Enzymatic activity was shown to be bicarbonate dependent and specific for cyanate as a substrate, suggesting that cyanate utilization in ...

Studies of the non-enzymatic decarboxylation of /3-keto acids have shown that it is the keto form of the 8-keto acid which loses CO2 to form an enol of the product. This was demonstrated for dimethylacetoacetic acid by Pedersen (1) and for dimethyloxalacetic acid by Steinberger and Westheimer (2). These latter authors studied the catalytic effect of metal ions on the decarboxylation reaction an...

Aspen (Populus tremuloides Michx.) leaf extracts contain a newly discovered enzyme activity that catalyzes the magnesium ion-dependent elimination of diphosphate from dimethylallyl diphosphate with rearrangement to form isoprene (2-methyl, 1-3-butadiene). This isoprene synthase activity has been partially purified. The nonenzymatic reaction of dimethylallyl diphosphate to isoprene, known to be ...

BACKGROUND Overconsumption of oxygen in mammalian cells often lead to the production of reactive oxygen species (ROS) resulting from different mechanisms. Escape of scavenging enzymes/components or nutritional failure are the most important origins. Plant-derived molecules may protect biological molecules either by quenching free radicals, delaying or preventing the ROS formation or by restorin...

Although several enzymatic approaches have been applied with this intent, the sequential use of enzymes covering both cellulolytic and proteolytic activity has never performed in seaweeds. Sequential these improved overall extraction yield by up to 160%, 30% 80% different seaweeds when compared control condition (water extraction), a carbohydrases’ cocktail alone proteases alone, respectively. ...