User talk:Mateen Rehman

Introduction To Enzymes Introduction to Enzymes Enzymes are the biological molecules that increase the speed of a chemical reaction in living organisms. You can say that enzyme is a substance that act as a catalyst in living organisms. The biological processes that occur within all living organisms are chemical reactions, and most are regulated by enzymes. Without enzymes, many of these reactions would not take place at a perceptible rate. Enzymes catalyze all aspects of cell metabolism. This includes the digestion of food, in which large nutrient molecules (such as proteins, carbohydrates, and fats) are broken down into smaller molecules; the conservation and transformation of chemical energy; and the construction of cellular macromolecules from smaller precursors. Enzymes are found in all tissues and fluids of the body. Catalysis of all reactions taking place in metabolic pathways are carried out by intracellular enzymes. The enzymes in plasma membrane govern the catalysis in the cells as a response to cellular signals and enzymes in the circulatory system regulate clotting of blood. Most of the critical life processes are established on the functions of enzymes. Enzymes structure Enzymes are a linear chain of amino acids, which give rise to a three-dimensional structure. The sequence of amino acids specifies the structure, which in turn identifies the catalytic activity of the enzyme. Upon heating, enzyme’s structure denatures, resulting in a loss of enzyme activity, that typically is associated with temperature. Substrate A substrate is a molecule acted upon by an enzyme. A substrate is loaded into the active site of the enzyme, or the place that allows weak bonds to be formed between the two molecules Active site In biology, the active site is the region of an enzyme where substrate molecules bind and undergo a chemical reaction. The active site consists of amino acid residues that form temporary bonds with the substrate (binding site) and residues that catalyse a reaction of that substrate (catalytic site)

Compared to its substrates, enzymes are typically large with varying sizes, ranging from 62 amino acid residues to an average of 2500 residues found in fatty acid synthase. Only a small section of the structure is involved in catalysis and are situated next to the binding sites. The catalytic site and binding site together constitute the enzyme’s active site. A small number of ribozymes exist which serves as an RNA-based biological catalyst. It reacts in complex with proteins.