Vertebrate Zoology
What is allosteric enzyme?
Allosteric enzymes have, in addition to an active site, another stereo-specific site to which an effector or modulator molecule can bind. When it does, the shape of the active site is altered so that it can or cannot bind substrate (allosteric stimulation or inhibition respectively). In this way the enzyme can be part of a [...]
Cofactors and coenzymes
Cofactors are metal ions. These ions commonly provide a needed change within an active site. Many enzymes use metal ions to change a non-functioning active site to a functioning one. In these enzymes, the attachment of a cofactor causes a shape change in the protein that allows it to combine with its substrate. The cofactors [...]
Factors affecting enzyme activity
Any condition that affects the three-dimensional shape of an enzyme will effect its activity. Two such factors that affect enzyme activity are temperature and pH. The shape of a protein is determined by its hydrogen bonds. Hydrogen bonds are easily disrupted by temperature changes. For example, most higher mammals have enzymes that function best within [...]
Chemical Nature and Function of enzyme
All enzymes are proteins. An enzyme molecule may contain one or more polypeptide chains. The sequence of amino acids within the polypeptide chains is characteristic for each enzyme, and is believed to determine the unique three-dimensional conformation in which the chains are folded. This conformation, which is necessary for the activity of the enzyme, is [...]
Basic structure of enzyme
Enzymes are globular protein molecules that have three-dimensional shape with atleast one surface region having an area with a crevice or pocket. The crevice occupies only a small portion of the enzyme’s surface and is known as its active site. Their shape often provide them with one or more active sites (domains) which bind temporarily [...]