Variations in the esterase activity during the germination period of Jatropha curcas seeds

Germination brings out the synthesis or activation of enzymes responsible for the degradation of seeds reserves. Among these enzymes, esterases are involved in the metabolic processes of germination and maturation of plants. They are constitutively expressed in seeds during germination to release the reserve materials for the growing embryo. In the present study, total protein content and esterase activity was monitored in germinating Jatropha curcas seeds. The esterase activity and specific activity observed were 9.07 µmoles/min/gm and 0.09258 IU/mg, respectively. Electophoretic analysis for esterase activity showed thirteen bands of esterases, among these 8 esterolytic bands were major and remaining were minor bands. The protein content and esterase activity decreased on 2nd, 4th, 5th and 8th day of seed germination and activity increased on 3rd, 6th, 7th day of germination. Similarly esterase activity increased on 7th day and decreased on 8, 9 and 10th day in the shoot tissue. ÂÂ

Extraction of β-galactosidase and β-glucosidase from the seeds of Tamarindus indica

<p>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.</p