A comparative study on depolymerization of chitosan by proteolytic enzymes

作者：Kumar ABV; Tharanathan RN^*

来源：Carbohydrate Polymers, 2004, 58(3): 275-283.

DOI：10.1016/j.carbpol.2004.07.001

• chitosanolysis
• proteases
• non-specificity
• low molecular weight chitosans
• chitooligomers

Proteolytic enzymes such as pepsin, papain and pronase caused depolymerization of chitosan, a co-polysaccharide of glucosamine and N-acetyl glucosamine residues linked by beta-1,4-glycosidic bonds. The pH optima of these enzymes towards chitosanolysis were different from that towards their own substrates, indicating the involvement of pH-sensitive conformational changes during specific and non-specific activities. The depolymerization reaction obeyed Michaelis-Menten kinetics and K-m and V-max values indicated higher affinity of pepsin towards chitosan. The chitosanolytic products were low molecular weight chitosans (LMWC, a major product), chitooligomers (COs) as well as monomers. Low molecular weight chitosans had molecular weight in the range, 4.1-10.0 kDa depending on the reaction time. FT-IR indicated a decrease in the degree of acetylation of LMWC. GPC and HPLC of COs showed a degree of polymerization of 2-8 with a preponderance of di- to hexamer including monomers.

• 出版日期2004-11-25