Double enzyme method for preparing medicinal dextran with controllable molecular weight

Abstract

The invention relates to a double enzyme method for preparing medicinal dextran with controllable molecular weight. The medicinal dextran comprises dextran 70, dextran 40 and dextran 20. The preparation steps of the medicinal dextran comprise two steps of: firstly, synthesizing high molecular dextran: firstly, preparing the high molecular dextran by catalyzing sucrose by adopting dextran, wherein the conversion rate of the sucrose converted into the dextran reaches over 95 percent; secondly, controllably degrading the high molecular dextran: carrying out catalytic degradation on the high molecular dextran into the medicinal dextran as the medicinal dextran by adopting dextranase with high enzyme activity and realizing the controllable degradation of the dextran; and after the reaction is ended, removing impure protein in the products by adopting a simple filtering method and obtaining dextrans with different molecular weights by adopting graded ethanol precipitation. The double enzyme method has the advantages of greenness, environment friendliness, low cost, simplicity and convenience; and in addition, according to the double enzyme method, the yield of products can be greatly improved and the medicinal dextran with high quality is obtained.

Description

technical field [0001] The invention relates to the fields of biopharmaceuticals and enzyme engineering, in particular to a process for jointly preparing medicinal dextran with controllable molecular weight by using dextran sucrase and dextranase. Background technique [0002] Dextran (Dextran) is a polymer formed by the dehydration of several glucans, which is mainly connected by glucose α-1, 6 glycosidic bonds. Dextran sucrase (Dextransucrase; E.C.2.4) produced by Leuconstoc mesenteriodes .1.5) The synthesized dextran contains 95% α-1, 6 glucosidic bonds, and contains a small amount of branched structures of other glycosidic bonds. Because of its many advantages such as safety and non-toxicity, it has been widely used in many fields such as medicine, industry and food. Polymer dextran can be used as a drug carrier, as well as a commonly used gel chromatography filler. Dextran 70, Dextran 40, and Dextran 20 are commonly used clinically, and are mainly used as plasma subst...

AI Technical Summary

Problems solved by technology

At present, foreign scholars have directly used bacterial strains producing dextran sucrase and dextranase to prepare medicinal dextran directly. Conducive to industrial production

In addition, some scholars use dextran sucrase and dextranase double enzymes to prepare medicinal anhydride, but due to the low yield (36%), it is not conducive to industrial production