EFFECT OF UV RADIATION AND TEMPERATURE ON PAPAIN ACTIVITY

Abstract

Papain (EC 3.4.22.2) is an endolytic cysteine protease derived from papaya latex (Carica papaya L.). Today, this enzyme is considered as an anti-inflammatory, anticoagulant and hemolytic agent, as well as a substance that accelerates tissue repair. Chitosan is classified as a universal sorbent that binds a wide range of substances of organic and inorganic origin. It has antimicrobial activity, biodegradability, non-toxicity and bioadhesive properties. The aim of our work is to study the combined effect of UV-radiation and temperature on the activity of free papain and papain immobilized on a matrix of medium and high molecular weight chitosan. Papain was chosen as the object of study, bovine serum albumin (BSA) and azocasein served as substrates for hydrolysis, medium- (Mr = 200 kDa, degree of deacetylation (DD) 82%) and high molecular weight (Mr = 350 kDa, DD = 94.85%) chitosan were used as carriers for immobilization. It has been shown that the enzyme becomes more resistant to changes in the temperature regime, as well as to UV irradiation after its immobilization. At 90°C, native papain is completely inactivated, while the sorbed enzyme on medium and high molecular weight chitosan retains 45 and 57% of its initial activity, respectively. After the sorption of papain on the polysaccharide matrix at doses from 151 to 6040 J/m2, the catalytic ability of the enzyme changed to a lesser extent than that of its soluble form. The proteolytic ability of the biocatalyst immobilized on high molecular weight chitosan after UV irradiation even increased by 13-27% of the initial level.