Enzymes allow scientist to cut the chromosome of DNA into various desired length. Each time a particular restriction enzyme or set of restrictions enzymes is used, the DNA is cut into the same number of pieces of the same length and composition. At least 80 restriction enzymes are now known. When restriction enzymes are used along with other enzymes that tie together loose ends of DNA, it becomes possible to remove a bit of DNA from one organism's chromosome and to insert it into another organism's chromosome. Also in Compton's Encyclopedia enzymes are referred to as a preserver.
Enzymes can also help in the increasing of shelf life for fresh fruits and vegetables.
In a recent experiment scientist were called upon to help out in the problem of soft tomatoes. When the tomatoes were aloud to ripen on the vine the were found to be to soft for shipping. For this reason most store bought tomatoes are picked green, refrigerated while shipped, and then treated with ethylene gas to bring on the red color. The enzyme responsible for fruit softening is polygalacturonase. Scientist have taken the polygalacturonase gene and have inserted it, in reverse orientation, into tomato plants, giving the plants two genes for the enzyme.