Classify the IUB system enzymes categories.
The enzyme commission of International Union of Biochemist (IUB) has classified enzymes into six categories on the basis of their functional specificity. Each category is further sub-divided into particular groups consisting of number of enzymes. Most of the enzymes end as ‘ase’. The first part of enzyme acts on the substrate on which the enzyme acts. According to International Union of Biochemist (IUB) system the enzyme categories are:
Oxidoreductase: Oxidoreductase is cytochrosme oxidase. Oxidoreductase catalyse oxidation reduction reactions. Oxido-reductase, acting on the CH.OH group of the donor, with enzyme NAD or NADP as the receptor.
Transferases: Transferases is asparatate transaminase. Transferases catalyse reactions which in value group transfer. It transfers a functionally important group from one molecule to other molecule.
Hydrolases: Hydrolyses are all digestive enzyme for example — pepsin, trypsin etc. Hydrolyses catalyse hydrolytic reactions. Hydrolase split molecules in two by the action of water. These reactions occur in the gut and transform large insoluble food molecules into smaller soluble ones which can be absorbed. Phosphatase which remove phosphate group from organic molecules by hydrolysis also fall in this category.
Lyases: Lyases are ribulose diphosphate carboxylase and pyruvate decarboxylase. Lyses catalyse reactions in which either a double bond is established due to the removal of a group is added to the double bond. lyases add or remove groups without involving water. This occurs in the stroma of chloroplasts.
Isomerases: Isomerases is phosphoglucomutose. Isomerases catalyse isomerisation reactions. Isomerases convert one isomer of a compound into a different isomer by distributing the atoms.
Ligases: Ligases is amino acyl synthetase. It is also called as synthetase catalyse those reactions in which the breakdown of pyrophosphate bond of ATP or similar triphosphate. Ligases link together two molecules at the expense of ATP.