(a)+About+enzymes

= = = ABOUT ENZYMES = ==== **Enzymes** are proteins produced by living cells that catalyze (increase the speed of a reaction) chemical reactions that are involved in the metabolism of living organisms. Without itself being altered in the process. It is also called a 'biological catalyst'. ====

An **Active Site** is a region on an enzyme that binds to a protein or other substance during a reaction

Without enzymes chemical reactions that are essentials for life would be too slow, and life would not be sustainable on the planet.

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Why are enzymes so specific? **Catalyst:** A substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change. **Substrate:** a substrate is a molecule upon which an enzyme acts. Enzymes are proteins that have a very specific structure. The region on the surface of an enzyme that is responsible for binding and converting the substrate into the product is called the active site. The active site, in addition on the structure of the enzyme as a whole, is very specific to the substrate it catalyzes (just like how a lock can only be opened with one key) Any substrate cannot fit into the active site of the enzyme. Such an interaction would be structurally incorrect. Each enzyme has its own substrate (or set of substrates, which are closely related compounds with high structural similarity). Its specificity allows it to catalyze certain reactions with similarities. **Enzymes are specific for:** a) the substrate b) the reaction It means that they catalyze the transformation of just one substrate or a family of substrates that are structurally related, catalyzing only one of the possible reactions of the substrate(s). Enzymes are usually very specific as to which reactions they catalyze and the substrates that are involved in these reactions. Complementary shape, charge and hydrophilic/hydrophobic characteristics of enzymes and substrates are responsible for this specificity. The lock and key: enzymes are specific to catalyze specific reactions. Types of Enzyme Specificity: A few enzymes exhibit absolute specificity; that is, they will catalyze only one particular reaction. Other enzymes will be specific for a particular type of chemical bond or functional group. In general, there are four distinct types of specificity:
 * Absolute specificity - the enzyme will catalyze only one reaction.
 * Group specificity - the enzyme will act only on molecules that have specific functional groups, such as amino, phosphate and methyl groups.
 * Linkage specificity - the enzyme will act on a particular type of chemical bond regardless of the rest of the molecular structure.
 * Stereochemical specificity - the enzyme will act on a particular steric or optical isomer.

This video explains enzymes' functions and its relation to specificity: [] enzyme pepsin & the enzymes on the membrane of mitochondria Pepsin breaks down proteins into polypeptides inside the stomach. These polypeptides will break down further into amino acids, dipeptides and tripeptides inside the small intestine. is an enzyme whose precursor form (pepsinogen) is released by the chief cells in the stomach and that degrades food proteins into peptides The molecules and some of the enzymes responsible for making ATP are located in and on the folds of these inner membranes (cristae). Check out these links: [] [] []