Alginate as an antiglycating agent for human serum albumin.

Hyperglycemia and the accumulation of advanced glycation endproducts (AGEs) in tissues and serum have important roles in diabetic complications. Therefore, the identification of anti-glycation compounds is attracting considerable interest. In this study, the interaction of human serum albumin (HSA) with fructose, in the absence and presence of alginate, was studied by circular dichroism, absorbance and fluorescence techniques.

Control of aggregation in protein refolding: cooperative effects of artificial chaperone and cold temperature.

Refolding of GuHCl-denatured recombinant-human growth hormone (r-hGH) was investigated in both dilution additive and artificial chaperone assisted modes. In both techniques, it was found that CTAB is a better additive (in dilution mode) or a capturing agent (in artificial chaperone method). Neither of the two techniques was capable of complete inhibition of aggregates formed during refolding process.

Kinetic aspects of alkaline phosphatase refolding in the presence of alpha-cyclodextrin.

To get a better understanding of the molecular aspects of protein folding, the refolding kinetic behavior of guanidine hydrochloride-denatured alkaline phosphatase (ALP) was studied in the presence of alpha-cyclodextrin (alpha-CD) through two different approaches: the dilution additive and the artificial chaperone-assisted methods. It was found that alpha-CD enhanced the recovered activity more than 50% via both approaches while decreased the refolding rate, perhaps due to engaging the hydrophobic patches of the protein in a rigid conformation. In contrast, detergents used in the artificial chaperone method increased the refolding rate significantly.

Artificial chaperone-assisted refolding of GuHCl-denatured alpha-amylase at low temperature: refolding versus aggregation.

Refolding of GuHCl-denatured alpha-amylase was investigated using the artificial chaperone-assisted method. Three different cationic detergents (CTAB, TTAB and DTAB) and two nonionic detergents (Tween 80 and Triton X-100) were evaluated as the capturing reagents along with alpha- and beta-CD as the stripping agents. The refolding yields, at a final protein concentration of 0.

Increased erythromycin production by alginate as a medium ingredient or immobilization support in cultures of Saccharopolyspora erythraea.

Erythromycin production by Saccharopolyspora erythraea immobilized in 2% (w/v) calcium alginate or grown in medium containing 20 g sodium alginate/l inoculated with free cells was almost twice more than that of the control. S. erythraea did not consume alginate, agar, dextran, silicon antifoaming agent or cyclodextrin as a carbon source, although, all of these increased the production of erythromycin.

Artificial chaperone-assisted refolding of chemically denatured alpha-amylase.

It is now well established that alpha-cyclodextrin (alpha-CD) is a valuable folding agent in refolding processes of several denatured enzyme solutions. The refolding of Gu-HCl denatured alpha-amylase in the dilution-additive mode revealed that alpha-CD enhanced the refolding yield by 20-30% depending upon alpha-CD concentration. However, the refolding efficiency of the Gu-HCl denatured alpha-amylase through the artificial chaperone-assisted method indicated that alpha-CD enhanced the activity recovery of denatured alpha-amylase by almost 50% and also increased the reactivation rate constant relative to the unassisted control sample.