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Flashcards in Enzymes as Biological Catalysts Deck (59)
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1

enzymes speed up the rate at which a reaction reaches _____

equilibrium

2

Enzymes DO NOT affect the equilibrium ____ of a reaction

position

3

what are enzymes made of?

mostly proteins - exceptions are some types of RNA - ribozymes are catalysts

4

enzymes can increase the rate of a reaction by a factor of up to __

10^20

5

Enzymes specifically bind and stabilise the ____ ___

transition state

6

what is the transition state?

the reaction intermediate species which has the greatest free energy

7

how do enzymes reduce the activation energy ?

they provide alternative pathways

8

what is glycogen storage disease?

an enzyme deficiency that results in failure of
glycogen to enter transition “phosphorylated” state

9

glycogen storage disease is caused by Defective ____ synthesis/breakdown in muscle, ____ & kidney

Defective glycogen synthesis/breakdown in muscle, liver & kidney

10

what is the most common enzyme to be defective in glycogen storage diseasE>

glucose 6 phosphate

11

what does a defect in glucose 6 phophate cause?

von gierke's disease

12

what are the symptoms of von gierks (5)

- hypoglycaemia
- skin and mouth ulcers
- hepatomegaly
- bacterial and fungal infection
- bowel inflammation and irritability

13

why do you get hypoglycaemia if you dont have glucose 6 - phosphate

you cannot convert glycogen to glucose

14

what is the treatment for glycogen storage disease?

- slow release glucose meal
- feed little and often

15

why are people with von gierks given corn starch ?

it is hard to metabolise so prevents hypoglycaemia

16

Catalytic activity of many enzymes depends on presence of small molecules, called ____ or____

cofactors or coenzymes.

17

what are cofactors ?

metal ions

18

what are coenzymes?

organic molecules

19

Metal cofactors form a ____ _____ ____ in the enzyme.

metal co-ordination centre

20

what can an enzyme be referred to if it has a metal co-ordination centre?

metalloprotein

21

Coenzymes mostly associate with the enzyme only ____

transiently

22

Coenzymes change ____ or-_____ during the course of the reaction, but are ______.

Coenzymes change charge or structure during the course of the reaction, but are regenerated.

23

what are tightly bound coenzymes caused?

prosthetic groups

24

what is an enzyme without a cofactor called?

apoenzyme

25

what is an enzyme with a cofactor called?

holoenzymes

26

apoenzyme + cofactor =

holoenzymes

27

give ezamples of some cofactors?

metal ions - zinc iron

coenzymes

28

metal ions are involved in ____ reactions

redox

29

many coenzymes are derived from ____

vitamins

30

many coenzymes are involved in ___ reactions (NAD, FAD)

redox