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 [...]
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 [...]
Most enzymes are of protein nature. But there are some exceptions. For example, a few RNA molecules show some catalytic action. These RNA molecules are known as ribozymes. These are actually ribonucleoprotein particles, i.e., made up of protein and RNA, but only RNA portion shows catalytic activity. Example- RNase P in E. coli acts as [...]
An enzyme is a biocatalyst that increases the rate of chemical reaction without being changed in the overall process. Enzymes change covalent bonds of some biochemical substances and transform that substance to a new substance. The substance that undergoes covalent modification is known as substrate of that enzyme and the newly produced substance is known [...]
There can be many optical isomers of a substrate. However, it is only one of the isomers which acts as a substrate for enzyme action eg.; for hydrolysis of poplypeptides at D- and L- amino acids- there are two types of enzyme needed which will act on D- and L- isomers of amino acids. Trypsin [...]
