Saturday, 19 November 2011
Enzymes are the substances present in the cell in the minute amounts and capable of speeding up chemical reactions which are associated with life processes; so any impairment of enzymic activity is evident by any change in the cell which could be death as well!!! So it is not wrong to say that any substance that have unique capacity of speeding up a chemical reaction along with accelerating the velocity of reaction without necessarily initiating it is called as CATALYST and enzyme duly qualify to fit into this property.
All enzymes are produced in the cell but some of them would function in the cellular environment and some will be secreted through cell wall. On this basis we have got two types of enzymes: the former ones are Intracellular enzymes and the latter ones are extracellular enzymes. Intracellular enzymes perform catabolic reactions and provide energy required by the cell. Extracellular enzymes make necessary changes on the nutrients in the medium to allow them to enter the cell.
Properties of Enzymes
Enzymes are proteinaceous in nature and therefore possess properties specific to the proteins i.e. they are non dialyzable and easily denatured by heat.
A complete enzyme is a Holoenzyme which is composed of a protein part and non protein part (organic molecule). The protein portion is referred to as Apoenzyme. The organic molecule is referred to as Coenzyme. In some cases non protein portion of an enzyme can be metal. In fact many enzymes require the addition of metal ions in order to be activated. these metal ions function in combination with the enzyme protein and they are regarded as cofactors.
In my next post i will be adding up some more notes for the inhibition & kinetics.