23 | Enzymes and Receptors

Question 1

What two types of catalyst are there?

Answer 1

Enzymes & Ribozymes

Question 2

Explain how the catalytic features arise!

Answer 2

Due to the geometrical arrangement of functional groups in a small number of amino acids in the active site

Question 3

Consequences of a reduced energy barrier!

Answer 3

Having the active site bound by an substrate leads to a conformational TS which lowers energy, thereby increasing reaction rate

Question 4

enzymes are collectively responsible for maintaining?

Answer 4

the metabolic needs of cells under diff. physiochemical conditions

Question 5

Through their individual catalytic activities, they control the ___ of a particular metabolic
or signalling pathway

Answer 5

rate

Question 6

A range of regulatory mechanisms operates to allow short-, medium- and long-term changes in activity – to prevent?

Answer 6

cell dysfunction

Question 7

The catalytic properties of an enzyme are often dependent upon?

Answer 7

presence of cofactors

Question 8

Individual enzymes are characterised by their?

Answer 8

specificity

Question 9

Explain a prosthetic group!

Answer 9

tightly bound cofactor to the enzyme

Question 10

What are isoenzymes?

Answer 10

Are enzymes that can take part as catalyst of the same reaction but differ in the amino acid content.

Question 11

most frequently exploited mechanism of action of drugs is the ____ ____ of an enzyme.

Answer 11

reversible inhibition

Question 12

____ is a phenomenological measure that describes the
concentration of inhibitor required to lower the enzyme activity to 50%

Answer 12

IC50

Question 13

Describe EC50

Answer 13

the concentration of inhibitor required to saturate enzymes. to give a 50 % biological response, related to potency.