Effect of the Chemical Modification of Dextran on the Degradation by Dextranase

Abstract

Dextran was modified using three different methods: a) partial periodate oxidation and subsequent reduction of the aldehyde groups, b) suc cinoylation and c) chloroformate activation with subsequent reaction with 2- hydroxypropylamine, ethylenediamine and tris(2-aminoethyl)amine. Degrada tion of these dextran derivatives by dextranases was investigated. It was observed that the rate of degradation decreased with increasing degree of chemical modification of the parent polysaccharide. The nature of modification had no significant influence on the rate of degradation.

Polymer Masked−Unmasked Protein Therapy. 1. Bioresponsive Dextrin−Trypsin and −Melanocyte Stimulating Hormone Conjugates Designed for α-Amylase Activation

“…16 Not surprisingly, it was easier to regenerate enzyme activity by addition of R-amylase than MSH-receptor binding owing to the easier accessibility of the low molecular weight substrate to the enzyme's active site. As shown previously for both chemically modified dextrans 26 and for dextrin, 17 the degree of modification governed the rate of degradation. The extent of regeneration of protein/peptide activity in these in vitro models is complex to interpret.…”

Preparation and characterization of nanoparticles based on dextran–drug conjugates

“…An enzyme, which is responsible for biodegradation of dextran and its derivatives in living organisms, is dextranase [5]. After degradation of the polymer into low molar mass fractions, esterases and other hydrolases can attack easily [29]. In a preliminary experiment, the number average molar mass in a particle suspension (sample 1) was reduced from 38,300 to 1300 g/mol upon treatment with dextranase for 4.5 h. The degradation of the dextran ibuprofen ester particles into lower molar mass fractions thus seems to be possible.…”

Biodegradable nanoparticles made from polylactide-grafted dextran copolymers

“…As already observed by several authors [30,33], the derivatization of biodegradable polymers like polysaccharides often reduces enzymatic degradability. In some case as for methacrylated dextran [30], degradation rate was reduced but similar degradation extents were attained.…”