Question

1. Some enzymes, require other molecules, co-factors, to become activated and/or to function.

a. In general, describe what type of molecule a co-factor typically is, what it does and the common types of chemical interactions it forms with the enzyme. In your explanation, include the terms: apoenzyme and holoenzyme, and describe how a cofactor affects the enzyme-substrate affinity.

b. Compare/contrast the two main classes of cofactors, and describe an example of each (other than the ones presented in lecture). PS: “describe” means to explain how the cofactor interacts with the enzyme and what the effects are

Answer 1

a) Holoenzyme is catalytical active part of enzyme. It is combination of apoenzyme and cofactor of it. In general cofactor is non protein of organic group (or) metallic ion of it. It helps in catalysis agent such as act as carrier molecule of it. where apoenzyme is inactive protein part of enzyme present in active binding site of enzyme, when cofactor interact with it turn active protein part then form holoenzyme. then substrate change into product of it. ex:-pyurvate acid+NADH-------->NAD+ Lactic acid here NADH is carrier molecule.

b)Cofactors are classfied into 2 types are:- 1)coenzyme and 2)prosthetic group. coenzyme is protein part of organic group, it helps in direct reaction of it which involves in stability of it. ex:-DNA is negatively charged due to presence of phosphate group to maintain equilibrium Mg+2 is present. prosthetic group which are inorganic group of non protein part which are bound tightly to enzyme. ex:- haem group of haemoglobin.