What is an enzyme?
An enzyme is a type of protein. It exists within all biological cells. Its job is to speed up chemical reactions. Most chemical reactions are slow, too slow to enable us to keep on living. Enzymes also cut down on the potential for error in various chemical reactions within the body. These errors could cause all sorts of mutations; these mutations could cause phenylketonuria, a human genetic disorder. Phenylketonuria is a condition in which the body lacks a certain enzyme, this disorder can lead to mental retardation. The enzyme metabolizes phenylalanine to tyrosine, too much phenylalanine is what leads to mental retardation.
Enzymes are not restricted to the human body however, many cleaners use enzymes. Cleaner enzymes will speed up the chemical reactions again, but this time they are helping break down proteins and starch stains in clothes, or on countertops, etc.
There are over 5,000 known enzymes today. It was in the late 1700′s that people first began to discover enzymes. People knew that saliva would convert starch to sugar, and with that in mind Louis Pasteur began studying the fermentation to sugar to yeast, and he came to the conclusion that fermentation was catalyzed by ‘ferments’ in the yeast. In 1897 Hans and Eduard Buchner inadvertently used yeast extracts to ferment sugar, even though there were no living yeast cells. They added a large amount of sugar and found that it also fermented. The term enzyme was used to describe the substance that brought about the fermentation of the sugar.

