Certain type II restriction modification gene systems can kill host cells when these gene systems are eliminated from the host cells. Such ability to cause postsegregational killing of host cells is the feature of bacterial addiction modules, each of which consists of toxin and antitoxin genes. With these addiction modules, the differential stability of toxin and antitoxin molecules in cells pl...

Enzyme engineering via immobilization techniques is a suitable approach for improving enzyme function and stability and is superior to the other chemical or biological methods. In this study chitosan nanoparticles were synthesized using the Ionic Gelation method and were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Transmission Electron...

To investigate the structural/functional role of the dimeric structure in Cu,Zn superoxide dismutases, we have studied the stability to a variety of agents of the Escherichia coli enzyme, the only monomeric variant of this class so far isolated. Differential scanning calorimetry of the native enzyme showed the presence of two well defined peaks identified as the metal free and holoprotein. Unli...

Halohydrin dehalogenase from Agrobacterium radiobacter AD1 is a homo-tetrameric protein containing three cysteines per 28 kDa subunit. Under oxidizing conditions the enzyme was found to be susceptible to inactivation which could be prevented by the addition of -mercaptoethanol or glycerol. Gel filtration experiments and SDS-PAGE analysis revealed that inactivation coincided with monomerization ...

adenosine deaminase is an aminohydrolase (ec 3.5.4.4) which participates in the purine metabolism where it degrades either adenosine or 2'-deoxyadenosine producing inosine or 2'-deoxyinosine, respectively. the enzyme contains a parallel alpha/beta -barrel motif with eight central beta strands and eight peripheral alpha helices. ada is located both in the cytosol and on the cell membrane. since ...

Integration of molecular catalysts inside polymeric scaffolds has gained substantial attention over the past decade, as it provides a path towards generating systems with enhanced stability well enzyme-like...

A novel L-lysine modified semi-crosslinked chitosan resin (LMCCR) was synthesized and demonstrated to be a promising enzyme support by studying the enzymatic properties of glucose oxidases (GODs) immobilized on it. The prepared LMCCR beads have large specific surface and excellent chemical stability. The insertion of flexible L-lysine spacers between chitosan backbone and the immobilized GODs (...

An electrical transducer for urea is described. The excellent stability of various types of urease enzyme electrodes developed in the author's laboratory is due to understanding the parameters which affect immobilized enzyme stability. Preliminary experiments have shown that a liquid layer of urease trapped in a double cellophane layer over a cation electrode may produce a useful enzyme electro...

In this review, factors that contribute to enhancing the stability of immobilized enzyme membranes have been indicated, and the solutions to each factor, based on examples, are discussed. The factors are divided into two categories: one is dependent on the improvement of enzyme properties, and the other, on the development of supporting materials. Improvement of an enzyme itself would effective...

besides the high starch content, sweet potato contains endogenous amylases where the two predominants are - and β-amylases. sweet potato is thought to be a promising source of β -amylase since β -amylase is one of the major protein in the tubers. this investigation has focused on the properties of β amylase from white-flesh sweet potato that has been grown in iran as a potential source for indu...