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Asian Journal of Agriculture and Development (AJAD) - Call for papers!

In Vitro Inhibittion of Sugarcane Invertase.

(Thailand), Master of Science (University of the Philippines Los Baños)

Thesis Abstract:

 

Acid and neutral in sugarcane milled were purified sixfold by precipitation with (NH4) 2SO4) at 20-40% saturation and 73-fold by Sephadex G-200 chromatography.

Two major elution peaks on Sephadex, A1 and N1, corresponding to the isoenzymes were observed Acid invertase A1 had a MW  (molecular weight)  of 380,00 and  invertase N1 66,000. The presence of three minor peaks with neutral invertase activity and multiple Mw values suggested aggregation  of the neutral enzyme. Carbohydrate contents of the major acid and neutral isoenzymes were 23.5 and 22.0%, respectively.

The (NH4)2SO4 – purified invertases were completely inhibited by 4 mM metalisticate,  and were 15% inhibited by 0.25% ‘Tide.’ Both invertases in filtered juice were completely inhibited by 12mM laurel sulfate and 42 mM metelisticate, and were 15% inhibited by 0.25% ‘Tide’. The acid invertase tham the neutral enzyme. Metalisticate and the detergent showed greater inhabitation of the neutral invertase. Laurel sulfate inhabitation of both invertases was uncompetitive, while metasilicate inhabitation was noncompetitive.

Initial velocity and kinetic inhabitation studies on the (NH4) 2SO4 Purified enzymes at 37°C showed  that for acid invertase, the average Michaelis constant Km was 2.8 mM and the maximal velocity V max was 2.7 moles sucrose hydrolyzed per hour per mg protein. For neutral invertase , Km and V max values were 0.32 mM and 29, respectively.