Preparation And Medicinal Function Of Cross-linked Chitosan-L-Aarginine Anion Resin

In this paper, modified chitosan(CTS) as immobilized carrier has been studied, which can be used as carrier of sustained release drugs or immobilized enzyme which used in nonaqueous-catalyzed synthesis of drug, etc.First,cross-linked chitosan(CCTS) was prepared by glutaraldehyde cross-linking, then cross-linked chitosan-L-Aarginine(CCTS-Arg) anion resin was gained through condensation reaction between CCTS and L-Arginine by dicyclohexylcarbon diimine (DCC). Compared with CTS, CCTS appears a new absorption peak belonged to C=N at 1520 cm-1, CCTS-Arg anion resin appears a new absorption peak belonged to amide bond at 1650 ~1310 cm-1 in IR spectra. A new peak belonged to methylene at 23.5 ppm appears and displacement of C1 changes obviously through 13C-NMR analysis. It is confirms through above evidence that Schiff base is formed by glutaraldehyde crossing between amino groups of CTS, and amide bond is formed between residues amino groups of CCTS and carboxyls of L-Arg.CCTS-Arg anion resin is porous microspheres, whose average diameter is about 2 mm and pore size is about 200μm and water contained 85.59 %. The resin can not dissolve in both acid and base, and the dry packing density is about 0.23 g/mL.The dynamic exchange equilibrium time of CCTS-Arg anion resin for L-glutamate is 2 h, and the biggest dynamic exchange capacity is 30.95 mg/g wet resin. Similarly, the time of the resin for Penicillin G Sodium Salt is 1 h, and the capacity is 11.32 mg/g wet resin; The time of the resin for Ampicillin Sodium Salt is 1.5 h, and the capacity is 9.79 mg/g wet resin; The time of the resin for Zn2+ is 50 min, and the exchange capacity is 1.21 mmol/g wet resin; The time of the resin for urea is 3 hours, and the capacity is 12.25 mg/g wet resin.Using CCTS-Arg anion resin as the carrier, immobilized Ttrypsin andα-Chymotrypsin are prepared by glutaraldehyde cross-linking. The optimum immobilization conditions for Ttrypsin are that time is 50min, glutaraldehyde concentration is 1.5 %, amount of Ttrypsin is 26.67 mg/g, activity recovery rate is 51.61 %, and main enzymatic properties for immobilized Trypsin are that temperature of reaction is 70°C, pH is 6.81,Km is 1.71 mg/mL, half-life is 48 days. The optimum immobilization conditions forα-Chymotrypsin are that time is 60 min, glutaraldehyde concentration is 1.0 %, amount ofα-Chymotrypsin is 20.00 mg/g, activity recovery rate is 68.95 %, and main enzymatic properties for immobilizedα-Chymotrypsin are that temperature of reaction is 70°C, pH is 5.92, Km is 17.60 mg/mL, half-life is 46 days.L-Histidine andβ-Alanine reacted by immobilizedα-Chymotrypsin catalyzing in micro-aqueous n-butanol system, while the rate of L-Histidine,β-Alanine and immobilizedα-Chymotrypsin is 1:1:10 (m/m/m), the rate of n-butanol and distilled water 19:1 (v/v), and temperature is 40°C, after one hour reaction a new peak at 325 nm appears which is characteristic absorption peak of carnosine. Therefore, carnosine is synthesized.