DEGRADATION OF FLAX PECTIN BY POLYGALACTURONASE OF CLOSTRIDIUM FELSINEUM AND SOME ASPECTS ON THE DETECTION OF PECTIN-METHYLESTERASE

Abstract

The conditions influencing the activity of polygalacturonase, produced by Clostridium felsineum, on flax pectin were studied. Three-quarters of the enzyme activity was achieved in the first 15min of the reaction at 30° and pH 4.0. At higher pH values, citrate-phosphate buffer was found to be less harmful than acetate buffer to the enzyme activity, probably due to the tying up of some calcium ions. On using dilute enzyme preparations, no chromatographically detectable galacturonic acids and no correlation between the reduction in viscosity and increase in reducing end groups of flax pectin were found. The contrary occurred when a concentrated enzyme preparation was used and no disappearance of the released oligogalacturonic acids to produce monogalacturonic acid was detected as the time of polygalacturonase action prolonged. This was taken as an indication that polygalacturonase had more affinity toward polymer flax pectin molecules than to lower oligogalacturonic acids. On the other hand, the acidity of the culture filtrate was found to be a limiting factor for detecting pectin- methylesterase by the hydroxamate method.