in this research, an enzyme modified electrode has been produced during the electropolymerization of aniline through incorporation of sulfite oxidase into a conducting polymer. then the bioelectrochemical response of resulted sulfite biosensor was investigated at different experimental conditions. study of  the stability of the resulted sulfite biosensor revealed that formation of a passive fil...

The complete time course of the hydrolysis of p-nitrophenyl phosphate catalyzed by the low molecular weight (acid) phosphotyrosyl protein phosphatase from bovine heart was elucidated and analyzed in detail. Burst titration kinetics were demonstrated for the first time with this class of enzyme. At pH 7.0, 4.5 degrees C, a transient pre-steady-state "burst" of p-nitrophenol was formed with a rat...

A pro-clotting enzyme capable of causing the gelation of clottable proteins in Limulw polgphemus (horseshoe crab) has been purified to apparent homogeneity as judged by sodium dodecyl sulfate-gel electrophoresis. The activation of the pro-clotting enzyme depended on the presence of both Ca’+ and endotoxin. It contained y-carboxyglutamic acids and gave a single NlI,-terminal lysine. The enzyme w...

Transpeptidase-catalyzed protein and peptide modifications have been widely utilized for generating conjugates of interest biological investigation or therapeutic applications. However, all known transpeptidases are constrained to ligating in the N-to-C orientation, limiting scope attainable products. Here, we report that an engineered asparaginyl ligase accepts diverse incoming nucleophile sub...

Waves and patterns in living systems are often driven by biochemical reactions with enzymes as catalysts and regulators. We present a reaction-diffusion system catalyzed by the enzyme glucose oxidase that exhibits traveling wave patterns in a spatially extended medium. Fronts and pulses propagate as a result of the coupling between the enzyme-catalyzed autocatalytic production and diffusion of ...

Metal ions play essential roles in about one third of enzymes [1]. These ions can modify electron flow in a substrate or enzyme, thus effectively controlling an enzyme-catalyzed reaction. They can serve to bind and orient substrate with respect to functional groups in the active site, and they can provide a site for redox activity if the metal has several valence states. Without the appropriate...

Bacterial α-amylase was immobilized in sol-gel matrices using different techniques and precursors (i.e. tetraethoxysilane and methyltriethoxysilane). Sol-gel entrapment procedures were adjusted to enhance the immobilized enzyme activity and the textural properties of the silica matrices. The addition of a template agent, the variation of aging and drying conditions or the gelation performed in ...

The cold gelation of preheated whey protein isolate (WPI) solutions at alkaline conditions (pH>10) has been studied to better understand the effect of NaOH in the formation and destruction of whey protein aggregates and gels. Oscillatory rheology has been used to follow the gelation process, resulting in novel and different gelation profiles with the gelation pH. At low alkaline pH, typical sol...

Thiolated polymers are widely used in hydrogels for drug delivery, tissue engineering, and biofabrication. The oxidation of thiols is spontaneous, resulting the formation disulfide bridges cross-linking polymers. process is, however, difficult to control initiated directly when thiolated components exposed ambient conditions, which significantly complicates handling materials. Here, we show a f...