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Pectinase is a general term for enzymes that break down pectin, a polysaccharide substrate that is found in the cell walls of plants. One of the most studied and widely used commercial pectinases is polygalacturonase. It is useful because pectin is the jelly-like matrix which helps cement plant cells together and in which other cell wall components, such as cellulose fibrils, are embedded. Therefore pectinase enzymes are commonly used in processes involving the degradation of plant materials, such as speeding up the extraction of fruit juice from fruit, including apples. Pectinases have also been used in wine production since the 1960s.it joins together with the sustrate at a ponit called the active site

[edit] Optimum environment

Like all enzymes, pectinases have an optimum temperature and pH at which they are most active. For example, a commercial pectinase might typically be activated at 45 to 55 °C and work well at a pH of 4.8 to 5. If it is hotter it will make the reaction go more quickly. However, the higher temperature will eventually denature the enzyme, ultimately destroying the enzymatic action.

Pectinase also breaks down pectin best at a pH of 4.8 to 5; too high or too low a PH would also result in the enzyme denaturing. The logical explanation of why the enzyme denatures would be that if the pH is decreased too much, there would be too many H+ ions around the protein and thus the H+ ions would be attracted to the places in the enzyme which were more negative than the enzyme, thus forming a hydrogen bond there. Also, if the pH is increased, there would be too many OH- ions and they would interact with the positive regions in the protein.

This negative or positive region could possibly be in the active site, and even if it is not it does end up disfiguring the enzyme. Due to the fact that the enzyme-substrate interaction is so specific, even the slightest deformity of the active site directly or indirectly will result in the enzyme involved not working properly. This change, if permanent, will render the enzyme useless. Pectinase is also very good for producing apple juice from apple sauce.