Physiology

Question 1

how much is the rate increased when carbonic anhydrase is added ?

Answer 1

0.1 –> 1,000,000 per second

Question 2

what are enzymes made up of?

Answer 2

proteins; amino acids and other chemical groups (eg. metal ion)
&/or RNA(eg. Ribosomes)

Question 3

what is K cat

Answer 3

the number of molecules of substrate that one enzyme molecule can convert in 1 second

Question 4

define prosthetic group or co-enzyme

Answer 4

metal ions or organic molecules

Question 5

define apoenzyme

Answer 5

an enzyme with ought an essential cofactor or coenzyme

Question 6

define holoenzyme

Answer 6

enzyme + coenzyme (complete machinery)

Question 7

where does trypsin hydrolyse phenylalanine, tyrosine, or tryptophan?

Answer 7

the peptide bonds at the C terminus

Question 8

what determines the activity and specificity of an enzyme?

Answer 8

the structure and chemistry of the active site

Question 9

what are the qualities of an active site?

Answer 9

• 3 dimensional structure
• site can come together from different parts of the polypeptide chain
• site forms a cleft or crevice
• many week non covalent interactions between substrate and active site groups

Question 10

what is induced fit

Answer 10

enzymes adjust binding

Question 11

what is it called when the enzyme is bound?

Answer 11

transition state

Question 12

what does the transition state mean for the reaction?

Answer 12

different pathway with lowering the activation barrier

Question 13

what is Michaelis complex?

Answer 13

enzyme-substrate complex

Question 14

what is the Michaelis -menten equation & what can it derive?

Answer 14

2. affinity, selectivity, efficiency, inhibitor characteristics, pharmacology

Question 15

what are drugs?

Answer 15

inhibiters – enzymes + receptors are the target

Question 16

what is the regulation of relevant metabolites?

Answer 16

product feedback inhibition, such as ATP. mechanism involves allosteric binding

Question 17

example of feedback inhibition :

Answer 17

threonine to isoleucine pathway - 5 enzymes, first is inhibited by isoleucine

Question 18

what is the regulation by proteins?

Answer 18

some are 1:1
some proteins mediate control of enzymes by interpreting other signals.
– does this by calcium and calmodium

Question 19

what is regulation with reversible covalent modification?

Answer 19

phosphorylation

Question 20

kinases and phosphates are regulated by what?

Answer 20

by revesable covalent modification - other enzymes or products

Question 21

controlled proteolysis:

Answer 21

made in the inactive form

Question 22

does allosteric regulation follow michealis mention kinetics?

Answer 22

no - it has a sigmoidal curve

Question 23

what does an inhibiter do?

Answer 23

mimic the substrate

Question 24

example of an inhibitor?

Answer 24

PALA - competitive
- this allows us to catches the protein in flagrant

Question 25

effect of PALA vs CTP:

Answer 25

PALA - promotes relaxed state – makes it favoured by substrate
CTP - less active t state

Question 26

what is the graph of ATCase?

Answer 26

sigmoidal - understood by imagining an allosteric enzyme as a mixture of two michealis mention enzymes.