Kinetic studies of Cocoonase from Mulberry Silkworm Bombyx mori L.
P. H.Thejaswini1, B.A. Parthasarathi2 and H.B. Mahesha3
1Department of Biotechnology, Maharani’s Science College for Women, Mysuru-570 005 [India] 2Department of Sericulture, Manasagangotri, University of Mysore, Mysore-570 006 [India] 3Department of Sericulture, Yuvaraja’s College, University of Mysore, Mysore-570 005 [India] #Authors contributed equally to the research work *Corresponding Author: hbmahesh@ycm.uni-mysore.ac.in
ABSTRACT
Cocoonase collected from four breeds of mulberry silkworm namely Nistari, C. nichi, KA and NB4D2. The crude enzyme was isolated and purified by column chromatography. The purified Fraction-I and Fraction-II was used to study specific activity, pH and temperature optima, Km value, Effect ofinhibitors and metal ions on cocoonase. The cocoonase enzymes from bivoltine breeds were more active than those from multi voltines. The pH optimum of cocoonase enzyme ranges between pH 7-8, and there was gradual loss of activity below pH 7 and above pH 8. The cocoonase enzyme showed maximum activity between 30-40C. Further, results of Km value exhibited that the Fraction-II from KA race showed more affinity towards the casein than those of other breeds studied. At the same time, Fraction-I from all the races showed more or less similar affinity towards casein. The results of metal ions on enzyme activity showed that some metal ions exhibited increased enzyme activity, whereas some of the metal ions reduced the enzyme activity. Of all the inhibitors studied except chicken egg white and Ragi Subtilisin inhibitor showed reduced enzyme activity.