Invertase purification

Van den Ende, W. and Van Laere, A., Purification and properties of an invertase with sucrose sucrose fructosyl transferase (SST) activity from the roots of Cichorium intybus L., New Phytol., 123, 31-37, 1993. 

Using the value of a determined above, the results of the standard assay made initially to check the enzyme activity, the assay in part C, and the given concentration of the enzyme stock solution in g L , calculate the specific activity of the enzyme— that is, the number of micromoles of sucrose hydrolyzed per minute per gram of enzyme present. (The specific activity of an enzyme preparation is of course a function of the purity of the enzyme. As inactive protein is removed from the preparation, the specific activity will rise. When the specific activity can no longer be increased by any purification method, a homogeneous enzyme preparation may have been achieved but proof of this depends on other criteria.) The exact chemical composition of invertase is still unknown, but its molar mass has been estimated at 100,000 g mol Combining this datum with your calculated specific activity, estimate the turnover number for the enzyme. 

Ross, H.A., McRae, D., and Davies, H.V, 1996, Sucrolytic enzyme activities in cotyledons of the faba bean (developmental changes and purification of alkaline invertase). Plant Physiol. 111(1) 329-338. 

Encapsulation of Enzyme. To prepare the enzyme-loaded PSt microcapsules, a primary emulsification was carried out on 20 mL of O.IM acetate buffer containing 600 mg of enzyme (invertase) and 800 mg of an emulsifier (Triton X-100) (5). The purification of the enzyme-loaded capsules, followed by polymer adsorption, was performed in the same manner as described in the previous section. 

Preparation. Hydrolysis of raffinose by invertase yields melibiose 80) and D-fructose. By the use of bakers yeast (top yeast), hydrolysis and simultaneous removal of the D-fructose by fermentation takes place. The sirup crystallizes directly or after purification through the octaacetate. 

Batistic et al. have used similar extraction and purification procedures to obtain from soil active acid and alkaline phosphomonoesterases (and other hydrolases, cellulase, B-glucosidase, invertase and proteinase), Salmine substituted for protamine as a precipitant of humic material from dialysed extracts. In this case complete flocculation of humic compounds was accompanied by extensive (about 60%) losses of enzymic activities from solution. The activities of the precipitated material were low and could not be restored. Enzymes remaining in dialysed supernatants were of enhanced (about ten fold) specific activities, and were further fractionated by... 

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