Pectinesterase plant

The presence of salts of univalent and bivalent cations increases, by several-fold, the activity of pectinesterases from higher plants, which is minimal in the absence of salts.38,50,57,6, 63,64 66,69,7° The activating effect of salts on pectinesterases of microbial origin is not so great, an increase by 1.5- to 2-fold being reported.51 56,63 76-78,80 Table III shows the concentrations of sodium chloride and calcium chloride that caused the maximal activation of pectinesterases of plant and microbial origin. The mechanism of activation has not yet been satisfactorily explained. 

It is not yet known whether the increase of these activities in the course of fruit ripening is due to a direct synthesis of the enzymes, or whether conversion of inactive precursors into the active enzymes is involved. There is also the possibility of (a) an effect of inhibitors present in unripe fruit on the activity of endo-D-galacturonanase, and (b) disappearance of such inhibitors in the course of ripening.184 For pectinesterase, it has been speculated that plants may be able to regulate the activity of this enzyme by metabolic control of the amount and proportion of certain, naturally occurring, fatty acids.82... 

Lineweaver and Ballou49 have proposed a pectinesterase unit ( PE. u. ) for expressing PM activity. One such unit is equivalent to 1/930 PMU under the same experimental conditions or the quantity of enzyme that, at 30° and optimum pH, will catalyze the hydrolysis of pectin at an initial rate of one milliequivalent ester bonds per minute in a standard substrate (0.5% citrus pectin containing 8-11% methoxyl) and 0.15 M sodium chloride. The use of the latter unit is unfortunate since the values obtained for the activity in ordinary plant materials are obtained in the third decimal place and because the experimental conditions are so... 

Plant pectinesterases are activated by cations, and their pH optima shift to lower values in presence of cations 61, 77). Mayorga and Rolz (78) proposed equations predicting the activity of pectinesterases as a... 

Through the centuries man has used pectic enzymes produced by microorganisms in natural fermentations to modify plant tissue to produce more useful products. One of the oldest fermentations is the process of retting, in which textile fibers, such as flax, hemp, and jute are loosened from their plant stems. Clostridium felsineum, one of the organisms involved in anaerobic retting, produced endopolygalacturonase and endopolygalacturonate lyase but not pectinesterase 178, 179). 

Pectinase Pectinesterase Pectinlyase Polygalacturonase Pectolytic Enzymes Cleavage of Plant (a-1,4) Polysaccharides Aspergillus Niger Disintegration of Plant Tissue. Reduction of Macerate Viscosity. Improved Extracta-bility of Juice-bound Flavours... 

Tsunetsugu, Moese, Baeck, Herbots Procter Gamble Detergent compositions comprising a pectinesterase enzyme Contains a pectinesterase useful for removal of body, plant, fruit, and vegetable juice soils... 

Other pectins with degree of esterification of about 10, 30 and 40% (Table I) were obtained by enzymic deesterification of the initial preparation. An orange pectinesterase was used and the pH of the reaction was 6 in order to avoid concurrent base-catalyzed saponification. The action of plant pectinesterase is known (16-18) to result in a blockwise arrangement of free carboxyl groups in the pectic molecules. The enzymic preparation does not contain depolymerase activities as shown by the constancy of the intrinsic... 

Demethylation of pectin has been the most obvious change observed in cell wall structure, both in the chilling injury of fresh cucumbers ( 7, 29) and during fermentation ( ). Bell et al. (30) showed that cucumber plants contain pectinesterase in all parts of the plant, including the fruit. As part of a series of studies of chilling injury in cucumber fruits, Fukushima and Yamazaki (29) found that a decrease in hot, water-soluble, high... 

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