Nomenclature of enzymes

Question 1

What are the six different groups of enzymes ?

Answer 1

1. Transferases : They transfer functiona;l groups from one molecule to another such as ( C- , N- , P- containing groups )
   Ex : Alanine aminotransferase (ALT)
2. Ligases : They join two molecules together by formation of bonds between C , O , S or N and hydrolysis of ATP / GTP
   Ex: Fatty acylCoA synthetase
3. Oxidoreductases : They move electrons between molecules
   Ex : Lactate dehydrogenase
4. Isomerases : They convert a molecule from one isomerase to another.
   Ex : Triose phosphate isomerase
5. Hydrolases : They break bonds by addition of water
   Ex : Lipases
6. Lyases : They break bonds without the addition of water ( C-C , C-N , C-S bonds )
   Ex : Aldolase A

Question 2

What are the components of the enzyme ?

Answer 2

1. Protein part ( Apoenzyme )
2. Non protein part ( Coenzyme and Cofactor )
3. Whole active enzyme ( Holoenzyme)
4. Substrate binding site ( Active site )
5. Allosteric sites

Question 3

What are vitamins ?

Answer 3

Vitamins are organic coenzymes ( Carriers ) or cofactors .

1. Thiamin ( vitamin B1 ) is a precursor of Thiamin pro-phosphate ( TPP ) which acts as oxidative decarboxylation
2. Riboflavine ( vitamin B2 ) : FMN and FAD which acts as hydrogen carriers
3. Nacin ( vitamin B3 ) : NAD+ and NADP+ which acts as hydrogen carriers
4. Pyridoxine ( Vitamin B6 ) : Pyridoxal phosphate which contributes in aminoacid metabolism
5. Lipoic acid which acts as oxidative decarboxylation
6. Pantothenic acid : CoA which contributes in Carbohydrates , fat and protein metabolism
7. Biotin ( Vitamin B7 ) which contributes in carboxylation reaction
8. Folic acid ( Vitamin B9 ) : Tetrahydrofolate which is a carrier of one carbon unit.