Re: What is Denaturing concerning Enzymes

Gemma,

Enzymes are proteins. Like all proteins, they are made up of a string of many amino acids that are chemically bonded together. Proteins might be just strands of molecular spaghetti, if not for the remarkable fact that they assume a very definite three-dimensional shape. This process is called protein folding. It is only in this final, folded shape that most proteins are active. When proteins become denatured, they lose this shape and become unfolded. Denatured proteins lose their characteristic biochemical activities. Enzymes, such as pepsin, are completely inactive when they become denatured.

The shape that a folded protein assumes depends on the identities of the specific amino acids that are incorporated into the protein. There are 20 amino acids that make up proteins. These amino acids differ in the identities of their side chain groups. Some of these side chains are neutral and nonpolar, some are negatively charged, some are positively charged. The interactions of the side chains with one another determines just how a particular protein will fold. Just how this happens, and the factors that control it, are areas of intense current research.

The forces holding proteins in their three-dimensional, folded state are often not very strong. Denaturing occurs when these forces are overcome, causing the protein to lose its shape. Proteins can be denatured by heating, or by treatment with various chemicals such as acids or bases. You can see proteins denaturing with your own eyes when you cook an egg. The white of an egg is largely protein, and upon heating, this material changes from a translucent liquid to a white opaque solid. This visual change is a result of the proteins becoming denatured as a result of heat.

You can find a more detailed explanation of protein denaturation on the Encyclopedia Britannica web site, http://www.britannica.com. A specific article on protein denaturation is at: http://www.britannica.com/bcom/eb/article/1/0,5716,119721+20,00.html