Enzymes are biological catalysts for biochemical reactions, they are also proteins produced by all living organisms and is very important to living things. Very much alike to other catalysts, the enzymes speeds up the rate of reaction by providing alternative reaction pathways with lesser activation energy to create an reaction. The catalytic functions are crucial in maintenance and activities for living things such as respiration, digestion and other important life processes. Chemical reaction that occurs in the living organism are dependent on the catalytic reactions of enzymes, which is why enzymes are also known as biotransformation. Catalyst are the substances that could increase the rate of reaction, and only small amounts of catalyst could generate the rate of reaction in a large amount. However, the enzymes themselves will not go through permanent changes and will remain unchanged through the whole process due to being composed of amino acids. Most chemical catalysts will catalyse wide ranges of reactions. But enzymes are very selective and will only catalyse specific reactions, due to the complex shapes of molecules. If the shape of the enzyme reshapes from the active site, it might no longer function at that point. Whereas the enzyme has been corrupted. Enzymes would be affected by temperature or pH levels. Some enzymes are even able to reverse a reaction from a direction that it would usually take by reducing the activation energy to a point where the reaction favors the reverse direction. The person who has discovered enzymes was french chemist Anselme Payen in 1833. There were also many people who has contributed the studies on enzymes such as swedish chemist Jon Jakob Berzelius who found out the catalytic reaction. In the year of 1926, the first crystallized enzyme was acquired by James B. Sumner. James was able to discover the purest form of the enzymes by isolating and crystallizing it. The discovery has earned him an nobel prize in 1947. How does an enzyme work What types of enzymes are there?In current understanding, there are around 4000 kinds of biochemical reactions known. Enzymes are classified depending on how they react with other compounds. Such as proteases the protein degrading hydrolytic enzyme, which breaks down proteins. Cellulases the enzyme that catalyzes hydrolysis (reaction that breaks down a bon due to water), which breaks down cellulose (insoluble substance the main factor of plant cells) . Lipases are glycerol ester hydrolases produced by plants, animals and microorganisms, that acts on carboxyl ester bonds in triglycerides which splits fats into glycerol and fatty acids. And amylases catalyses the hydrolysis of starch into sugars for example, glucose and maltose.