Protein component (apoenzyme) is very important in Enzyme activity. It is because apoenzyme is a site for substrate to attach and to form an active Enzyme. The part of enzyme to which the substrate attaches is called enzyme active side. Substrate is the material or molecule catalyzed. by an enzyme. It can be in the form of carbohydrate, protein, and fat.
non-protein component (prosthetic group) is stable in relatively high temperature and does not convert at the end of reaction. Prosthetic group consists of cofactor and coenzyme. Cofactor is composed of anorganic matters that are generally Metal, e.g. Cu, Fe, Mn, Zn,Ca, K, and Co. Coenzyme is composed Of non-protein organic matters that do not tightly attach to Protein part of an enzyme. For examples are NAD, NADP, and Coenzyme A.
Enzyme is able to accelerate a reaction because it can decrease activation energy
source: biology. The unity and Diversity of life 2004.