A New Method The Follow-up of Galacturogenic Polygalacturonase and Pectin-Methylesterase Activity by Colloid Tiration

Abstract

In the hydrolysis process of pectin by the pectic enzymes of Sclerotinia libertiana Fcl decomposition ratios resulting from the col-loid titration method increase gradually from the initial to the final stage of reaction, amounting to about 100 percent at their best conditions. These tendencies are similar to that of iodmetry, but dissimilar to that of the viscometric method, in which the decom-position ratios increase sharply at the initial stage of reaction, while a little afterwards. (See Table I.) In the case of pactic acid used as a substrate, these matters are also the same as above. (See Table II.) In the case of the hydrolysis of pectin or pectic acid by the exo- and endo-enzymes of Asp. niger (which contain a strong DPG but little GPG and PM), the decomposition ratio found by the viscometric method increases, but the decompositions are scarcely observ by colloid titration. In this case, the fore tion of reducing sugars observed is also litt (See Tables III. and IV). In consequence, it has, been concluded th the colloid titration method is specific ai sensible to the action of GPG or PM, b insensible to the action of DPG.