Paper on Enzymes

This essay has a total of 385 words and 2 pages.


Enzymes are proteins, composed of polypeptide chains and non-protein groups. Their
function is to help with the reactions of many cells and molecules by serving as
catalysts. A catalyst is a substance that allows the activation energy required for a
reaction by forming a temporary association with the molecules that are reacting. During
this process, the catalyst itself is not permanently altered in the process, and so it can
be used over and over again. Because of catalysts, cells are able to carry out chemical
reactions at a great speed and at comparative low temperatures.

Almost 2,000 different enzymes are now known, each of them capable of catalyzing a
specific chemical reaction. The molecule (s) on which an enzyme acts is known as its
substrate. For example, sucrose is the substrate for the enzyme sucrase. Enzymes have
specific structures that only its specific substrate will fit into. The polypeptide chains
of an enzyme are folded in such way that they form a grove or pocket on the surface. The
substrate fits in to this grove, which is the site of reactions catalyzed by the enzyme,
or active site. Recent studies of enzyme structure have suggested that the active site is
flexible. The binding between enzymes and substrate appears to alter the shape of the
enzyme. This induces a close fit between the active site and the substrate. It is also
believed that this may put some strain on the substrate molecule facilitating the

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