- Shlini Purushothaman*, Siddalinga Murthy K R
- Central College Campus, Bangalore University, Bangalore, Karnataka. India
The enzymes β–galactosidase and β–glucosidase were extracted from the tamarind seeds using different buffers at different pH.Highest activity was obtained with 10 mM sodium acetate buffer, pH 5.6 and 10 mM tris buffer, pH 7.4. The effect of NaCl and Triton X–100 at different concentrations on the extraction of the enzymes indicated 10 mM sodium acetate buffer, pH 5.6 containing 1 M NaCl as a better extractant of the enzyme.
The enzyme assay was carried out using p–nitrophenyl–β–D–galactoside and p–nitrophenyl β–D–glucoside as substrates. Highest enzyme activities were observed on 6th and 24th day of germination. The protein content gradually decreased upto 5th day of germination and suddenly increased on 6th day. However, on subsequent days of germination, the protein content greatly decreased upto 11th day.
During the latter period of germination (18th day onwards) the content remained almost constant.The kinetic parameters varied for both β–galactosidase and β–glucosidase. The activity of β–galactosidase was show to have an optimal operating condition at pH 5.5 and a temperature of 500C. The thermostability of the enzyme was in the range of 400C – 700C with the pH stability in the range of 5.0 – 7.0. The Km and Vmax values for pNPGal were determined as 66μM and 2.27nmolesmin-1.
In contrast the activity of β–glucosidase was shown to have an optimal operating condition at pH 5.0 and a temperature of 300C. The thermostability of the enzyme was in the range of 270C – 350C with the pH stability in the range of 4.0 – 7.0. The Km and Vmax values for pNPGlu were determined as 121μM and 5.26nmolesmin-1. The presented study is a preliminary work carried out for the standardization of protocols. The purification and characterization of β–galactosidase and β–glucosidase is under progress.
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