Viscera of Labeo rohita: A Potential Source of Trypsin for Industrial Application

ABSTRACT

The serine protease trypsin was isolated and purified from the digestive system of carp Labeo rohita rohu by ammonium sulphate precipitation, ion exchange, and affinity chromatography. The purified enzyme showed high activity between pH 7.0 and 9.0. The activity was maximum at 40°C. Incubation of the purified enzyme with CaCl₂ (2 mM) stabilized the enzyme activity for 8 h. The enzyme showed stability at 30 and 40°C for 1 h, but above 40°C, enzyme activity was reduced. The kinetic constants were recorded as K_m (0.104 mM), k_cat (44.25 s⁻¹), and catalytic efficiency (427.54 s⁻¹ mM⁻¹). Monovalent, bivalent, and trivalent ions (Li⁺, K⁺, Hg²⁺, Al³⁺, Mg^2+, Cd^2+, Co^2+, Zn²⁺, and Al³⁺) influenced the enzyme activity. Phenylmethylsulfonylflouride, soybean trypsin inhibitor, and N-α-p-tosyl-_L-lysine chloromethyl ketone completely inhibited the enzyme activity, while ethylenediaminetetraacetate caused partial inhibition. Molecular mass of the purified enzyme was 22.46 kDa. The pH and temperature stability of enzyme may be useful for its industrial applications.

KEYWORDS:

• Labeo rohita
• thermostable
• trypsin
• molecular mass

Acknowledgments

Authors would like to thank Department of Science and Technology, DST, New Delhi for financial support in the form of project. B.K. Khangembam acknowledged the University Grants Commission, UGC, New Delhi, India for providing the CSIR-UGC fellowship during the research work.

Additional information

Funding

This work was supported by the Department of Science and Technology, Ministry of Science and Technology [No. SR/SO/AS-04/2009, dated 29/10/2009]