Diseases

Question 1

Describe the disease: Phenylketonuria (PKU)

Answer 1

Incidence: Autosomal recessive disease, affects about 1 in 8,000-10,000 newborns.
Cause: Defective Phenylalanine Hydroxylase.
Clinical symptoms: Severe mental retardation.
Biochemical symptoms: characterized by greatly
increased concentrations of phenylpyruvate (keto acid of Phe) in blood and urine.
Treatment: Decrease phenylalanine in the diet.

Question 2

Describe the disease: Cardiovascular Disease

Answer 2

Incidence: Most common cause of death in New Zealand, accounting for about 33% of deaths in NZ.
Cause: Blockage of arteries that supply oxygen and nutrients to the heart.
Clinical symptoms: Chest pain, shortness of breath, pain in one or both arms, nausea, and often death (Heart attack).
Biochemical symptoms: Elevated levels of creatine kinase, aspartate aminotransferase, & lactate dehydrogenase.
Treatment: Blood thinners, angioplasty and rest.

Question 3

Describe the disease: Cancer

Answer 3

Incidence: Second most common cause of death in NZ, with lung, colorectal, and breast cancer being the most common.
Cause: - Switching “on” of oncogenes, switching “off” of tumour suppressor genes, or both. Inherited or caused by mutation.
Clinical symptoms: Many different, all caused by tumour growth that infects healthy tissue.
Biochemical symptoms: Upregulation of GLUT1 and GLUT3 and elevation of hypoxia-inducible transcription factor (HIF-1). Increased levels of glycolytic enzymes & vascular endothelial growth factor (VEGF).
Treatment: Chemotherapeutic agents including 2-deoxyglucose, ionidamine & 3-bromopyruvate (Hexokinase inhibitors) and imatinib (GLEEVEC), which inhibits a tyrosine kinase that promotes the synthesis of hexokinase.

Question 4

Describe the disease: Glycogen storage disease type 0

Answer 4

effects glycogen synthase, which affects the liver and has symptoms of low blood glucose, high ketone bodies, and early death

Question 5

Describe the disease: Glycogen storage disease type Ia (von Gierke’s)

Answer 5

Effects glucose -6- phosphatase, which affects the liver and has symptoms of Enlarged liver and kidney failure

Question 6

Describe the disease: Glycogen storage disease type Ib

Answer 6

Effects microsomal glucose -6- phosphate translocase, which affects the liver and has symptoms of enlarged liver, kidney failure, high susceptibility to bacterial infections

Question 7

Describe the disease: Glycogen storage disease type Ic

Answer 7

Effects microsomal Pi transporter, which affects the liver and has symptoms of enlarged liver and kidney failure.

Question 8

Describe the disease: Glycogen storage disease type II (Pompe’s)

Answer 8

Effects lysosomal glucosidase, which affects skeletal and cardiac muscle. Has symptoms of: infantile form: death by age 2, Juvenile form: muscle defects, Adult form: muscular dystrophy

Question 9

Describe the disease: Glycogen storage disease type IIIa (Cori’s or Forbes’s)

Answer 9

Effects debranching enzyme, which affects liver as well as skeletal and cardiac muscle. It has symptoms of Enlarged liver in infants and myopathy( Muscle dysmorphia)

Question 10

Describe the disease: Glycogen storage disease type IIIb

Answer 10

Effects liver(ONLY) debranching enzyme, which affects the liver. Has symptoms of the enlarged liver in infants.

Question 11

Describe the disease: Glycogen storage disease type IV (Anderson’s)

Answer 11

Effects the debranching enzyme, which affects the liver and skeletal muscle. Has symptoms of Enlarged liver and spleen, myoglobin in urine.

Question 12

Describe the disease: Glycogen storage disease type V (McArdle’s)

Answer 12

Effects muscle phosphorylase which affects the skeletal muscle. Has symptoms of exercised induced cramps or pain, myoglobin in urine

Question 13

Describe the disease: Glycogen storage disease type VI (Here’s)

Answer 13

Effects liver phosphorylase, which affects the liver. Has symptoms of enlarged liver

Question 14

Describe the disease: Glycogen storage disease type VII (Tauri’s)

Answer 14

Effects muscle PFK-1 which affects the muscle and erythrocytes. Have symptoms of exercise-induced cramps and pain, myoglobin in urine, and hemolytic anemia

Question 15

Describe the disease: Glycogen storage disease type VIb, VIII, or IX

Answer 15

Effects phosphorylase kinase, which affects the liver, leukocytes and the muscle. Has symptoms of enlarged liver

Question 16

Describe the disease: Glycogen storage disease type XI (Fanconi-Bickel)

Answer 16

Effects GLUT2, which affects the liver and has symptoms of failure to thrive, enlarged liver, rickets, and kidney dysfunction

Question 17

How can enzymes help diagnose a heart attack?

Answer 17

After a heart attack, different enzymes will be present in the tissue at different times.
1h = mitochondrial AST
12h = LDH-5 (M4)
18h = CK
1day = cytoplasmic AST
5days = LDH-1 (H4)

Question 18

Can diseases be caused by enzymes?

Answer 18

Yes, either by the deficiency in enzymatic activity, or the excess of.

Question 19

Why are enzymes targeted when fighting the flu?

Answer 19

Neuraminidase inhibitor, prevents enzymes from cleaving receptor, thus preventing cells containing the flu virus from replicating in the body.

Question 20

What is the Michaelis Menton theory?

Answer 20

E + S -> ES -> E + P

Question 21

What are the three assumptions of the Michaelis Menton theory?

Answer 21

1) Steady-state conditions
2) [S]&raquo_space;[E]
3) [S]&raquo_space;[P] (Initial conditions)

Question 22

What is the difference between irreversible and reversible inhibitors?

Answer 22

Irreversible will bing covalently to the active site, denature a functional group of the enzyme or form a non-covalent complex with the enzyme. Reversible however will bind the enzyme reversible with competitive, uncompetitive, or mixed modes of inhibition

Question 23

How do competitive inhibitors work?

Answer 23

it will bind the active site to compete with substrates. Lineweaver graph conjoins along the y-axis.

Question 24

How do uncompetitive inhibitors work?

Answer 24

It will bind the enzyme in an area that is not the active site, creating an ESI complex, inhibiting the transformation of the substrate. Its Lineweaver graph will all be parallel.

Question 25

How do mixed inhibitors work?

Answer 25

Mixed inhibition is a mix of both, and so can bind the active site, or not the active site to inhibit the enzyme. This Lineweaver graph will converge on the left of the y-axis.

Question 26

What are the 9 most common enzymes?

Answer 26

Kinase
Phosphorylase
Phosphatase
Dehydrogenase
Mutase
Isomerase
Hydratase
Synthase
Synthetase

Question 27

What do Kinase enzymes do?

Answer 27

This enzyme catalyses transfer of molecules onto other molecules from hydrolysed ATP or other high energy sources.

Question 28

What do Phosphatase enzymes do?

Answer 28

Catalyses the cleavage of a phosphate to yield the dephosphorylated product and inorganic phosphate. – Removes phosphates

Question 29

What do Dehydrogenase enzymes do?

Answer 29

Catalyses redox reactions. Commonly uses NADH/NAD+, NADPH/NADP+, or FADH2/FAD as cofactors. Can act as cofactors, binding the active site to be able to react with the required substrates.

Question 30

What do Mutase enzymes do?

Answer 30

Catalyses the shift of a phosphoryl group from one atom to another within the same molecule. Quaternary structures allow this to happen by positioning molecules in a certain way.

Question 31

What do Isomerase enzymes do?

Answer 31

Catalyses the conversion of one isomer to another, through moving substituents. Stereoisomerase change R to S and vice versa.

Question 32

What do Hydratase enzymes do?

Answer 32

Catalyses the addition of or removal of water.

Question 33

What do Synthase enzymes do?

Answer 33

Catalyses synthesis of a product without the use of a high energy source (Eg: ATP)

Question 34

What do Synthetase enzymes do?

Answer 34

Catalyses synthesis of a product using a high energy source.

Question 35

What do Phosphorylase enzymes do?

Answer 35

Catalyses covalent addition of inorganic phosphate to a molecule – Can cleave through this process