tailieunhanh - Báo cáo khóa học: Non-specific depolymerization of chitosan by pronase and characterization of the resultant products

Pronase (type XXV serine protease fromStreptomyces griseus) efficiently depolymerizes chitosan, a linearbfi1,4-linked polysaccharide of 2-amino-deoxyglucose and 2-amino-2-N-acetylamino-D-glucose, to low-molecular weight chitosans (LMWC), chito-oligomers (degree of poly-merization, 2–6) andmonomer. The maximumdepolymeri-zationoccurredatpH C,andthereactionobeyed Michaelis–Menten kinetics with aKmof mgÆmL )1 and Vmaxof nmolesÆmin )1 Æmg )1 . | Eur. J. Biochem. 271 713-723 2004 FEBS 2004 doi Non-specific depolymerization of chitosan by pronase and characterization of the resultant products Acharya B. Vishu Kumar1 Lalitha R. Gowda2 and Rudrapatnam N. Tharanathan1 1Department of Biochemistry and Nutrition department of Protein Chemistry and Technology Central Food Technological Research Institute Mysore India Pronase type XXV serine protease from Streptomyces griseus efficiently depolymerizes chitosan a linear bfi1 4-linked polysaccharide of 2-amino-deoxyglucose and 2-amino-2-N-acetylamino-D-glucose to low-molecular weight chitosans LMWC chito-oligomers degree of polymerization 2-6 and monomer. The maximum depolymerization occurred atpH C and the reaction obeyed Michaelis-Menten kinetics with a Km of mg-mL-1 and Vmax of nmoles-min-1-mg-1. The molecular mass of the major product LMWC varied between kDa depending on the reaction time. Scanning electron microscopy of LMWC showed an approximately eightfold decrease in particle size and characterization by infrared spectroscopy circular dichroism X-ray diffractometry and 13C-NMR revealed them to possess a lower degree of acetylation hydration and crystallinity compared to chitosan. Chitosanolysis by pronase is an alternative and inexpensive method to produce a variety of chitosan degradation products that have wide and varied biofunctionalities. Keywords chitosan chito-oligomers low-molecular weight chitosan pronase structure. Chitosan is the de-N-acetylated derivative of chitin a linear polysaccharide of P1fi4-linked 2-deoxy-2-acetamido-D-glu-cose units 1 that constitutes the exoskeleton of invertebrates and is one of the components of the cell walls of fungi. It has wide and varied applications in medicine agriculture pharmaceuticals and the food industry 1 2 which is attributed to the biofunctionality of the amine moiety that confers both cationic polyelectrolyte and chelating properties. Despite .