co-enzymes

Question 1

what are co-factors and co-enzymes

Answer 1

They are small molecules that many enzymes depends on for catalysis of reaction

Question 2

The enzyme without its cofactor is called

Answer 2

apoenzyme

Question 3

When it has its cofactor its called

Answer 3

holoenzyme

Question 4

what are co-factors

Answer 4

Co-factors are simple inorganic ions that promote enzyme function e.g. Zn Cu,Fe.
Make it fold and create an active site
Enhance the charge in the active site to improve substrate binding

Question 5

what co-factor does amylase require

Answer 5

amylase requires chloride ions

Question 6

what are co-enzymes

Answer 6

Small organic molecules attach to activate the enzyme and detach when reaction completed to deactivate the enzyme..
Coenzymes act as transporters of chemical groups from one reactant to another.

Question 7

give examples of co-enzymes

Answer 7

Most often these are vitamins e.g. Niacin, riboflavin

Question 8

what are isozymes?

Answer 8

Isozymes (also known as isoenzymes) are enzymes that differ in amino acid sequence but catalyse the same chemical reaction.

Question 9

what are the differences in the isozymes?

Answer 9

These enzymes usually display different kinetic parameters (e.g. different Km values), or different regulatory properties.

Question 10

what permits the fine-tuning of metabolism to meet the particular needs of a given tissue or developmental stage

Answer 10

isozymes

Question 11

Hurler syndrome is an enzyme deficiency disease.what is it?

Answer 11

• abnormal bone structure and developmental delay
• accumulation of glycosaminoglycan Heparan sulfate (long chain sugar molecule soften found in mucus & fluid around the joints) .

An enzyme responsible for the degradation of mucopolysaccharides in lysosomes

Enzyme replacement therapy
& bone marrow replacement

Question 12

Niemann-Pick disease

Answer 12

Lack acid sphingomyelinase (ASM)

.This lysosomal enzyme is required to metabolise the lipid sphingomyelin

If ASM is absent or not functioning properly, sphingomyelin accumulates within the cell, eventually causing cell death and the malfunction of major organ systems.

Question 13

tay sachs disease

Answer 13

Progressive deterioration of nerve cells and of mental and physical abilities that commences around six months of age and usually results in death by the age of four.
Gangliosides , cell membrane components, accumulate in the brain’s nerve cells
Functional Hexosaminidase-A is absent from lysosymes

Question 14

Homocystinuria

Answer 14

Mutations in the CBS gene
Cystathionine beta-synthase. This enzyme acts in a chemical pathway responsible for converting the amino acid homocysteine to a cystathionine.

As a result of this pathway, other amino acids, including methionine, are produced.

Mutations in the CBS prevent homocysteine from being used properly. As a result, this amino acid and toxic by-products substances build up in the blood.

Question 15

types of enzymes

Answer 15

oxidoreductases
2= transferases
3= hydrolases
4= lyases
5= isomerases
6= ligases

Question 16

TRANSFERASES

Answer 16

Transferases are enzymes that catalyse the movement of a functional group from one molecule to another. These functional groups are very diverse can include phosphate, methyl and glycosyl groups.

example: kinases

Question 17

LYASES

Answer 17

Lyases catalyse lysis reactions that generate a double bond. These are a type of elimination reaction but are not hydrolytic or oxidative. The reverse reaction catalyses an addition reaction, where a substrate is added to a double bond. These are often referred to as synthase enzymes.

pyruvate carboxylase

Question 18

ISOMERASES

Answer 18

Isomerases are enzymes that can catalyse structural changes within a molecule. There is only one substrate and one product with nothing gained or lost, so they represent only a change in shape. The diagram shows a simple example of this sort of reaction.

Question 19

LIGASES

Answer 19

Ligases are responsible for the catalysis of ligation; the joining of two substrates. Usually, chemical potential energy is required, so the reaction is coupled to the hydrolysis of a diphosphate bond in a nucleotide triphosphate such as ATP.

Question 20

HYDROLASES

Answer 20

Catalyse hydrolysis; the breaking of single bonds through the addition of water.

Huge variety of hydrolase enzymes. eg, the digestive enzymes that are classified based on their target.

They are termed exo or endo depending on where they cut. Endo enzymes cut in the middle of the chain, whereas exo enzymes cut at the end of the chain to release an individual monomer.

Question 21

give some examples of digestive enzymes:

Answer 21

Proteases/ peptidases cleave peptide bonds between amino acids in order to breakdown proteins

• Lipases break down lipids into fatty acids and glycerol by cleaving ester bonds
• Nucleases cleave phosphodiester bonds between nucleotide subunits in nucleic acids