enzymes I

Question 1

what are enzymes?

Answer 1

Proteins that speed up the rate of chemical reaction by providing a different pathway

Question 2

functions of enzymes

Answer 2

Digestion of carbohydrates, fats and proteins

Blood clotting (thrombin, thromboplastin) 

Defence-immune system-activation of complement 

Movement 

Nerve condition

Question 3

how do enzymes speed up the rate of reaction?

Answer 3

Increase rate of reaction by choosing the pathway with a lower activation energy

Question 4

What are the properties of enzymes?

Answer 4

Specific

Do not change position of equilibrium 

Enzyme defects cause disease

Question 5

what is a cerebroside?

Answer 5

glycosphingolipids, which are an important component in animal muscle cells

Question 6

Active site

Answer 6

3D cavity binds to substrate using forces like electrostatic, hydrogen bonding, hydrophilic and hydrophobic

evidence from X-ray crystallography 

kinetic studies of enzyme activity

Question 7

induced fit theory

Answer 7

the active site senses the substrate and the active site changes shape slightly

Question 8

substrate binding

Answer 8

there is a limit to how many substrates an enzyme can process in a given time

an increase in concentration increases rate at which product is formed eventually reaching a maximum value (Vmax) 

another parameter used to characterize an enzyme is its Km (the concentration of substrate that allows the reaction to proceed at one half its maximum rate (0.5 Vmax)

Question 9

What are the drug targets?

Answer 9

antibiotics (penicillin’s inhibit cell wall synthesis)
anti-inflammatory agents (aspirin block prostaglandin)
anticancer drug (methotrexate is a folate analogue
interferes with synthesis of DNA precursors)

Question 10

what diseases are caused by enzyme defects?

Answer 10

phenylketonuria - cannot convert phe to tyr
glycogen storage disease
tay sachs disease - membrane cerebroside

Question 11

lysozyme

Answer 11

attacks polysaccharide capsid that bacteria has
bacteria under really high osmotic pressure
lysozyme has a long cleft for its active site and binds to one of the polysaccharide chains in the capsule
active site big enough to bind 6 covalently linked polysaccharides
lysozymes changes shape of fourth sugar along, making it susceptible to water to make a break in the chain