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Flashcards in BioChem Deck (153)
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1

Oxidoreductases

Transfer elecltrons from a donor to an acceptor

2

Transferases

Transfer a functional group

3

Isomerases

Rearrange / isomerase a molecule

4

Lyases (syntheses)

Add or remove atoms to or from a double bond

5

Ligases “synthetases”

Form (C-O C-S C-N C-C) bonds with the hydrolysis of atp

6

Hydrolases

Cleave bonds via the addition of water

7

Enzyme that uses Cu as a cofactor

Cytochrome c oxidase

8

Enzyme that uses Fe as cofactor

Heme proteins (hemoglobin and myoglobin) need Fe to bind O2

9

Enzyme that requires Mg as a cofactor

ATPases

10

Enzyme that requires Se as a cofactor

Glutathione peroxidase- detoxifies hydrogen peroxide

11

Enzyme that requires Zn as a cofactor

Superoxide dismutase - binds the free radical of molecular oxygen

12

2 types of coenzymes

Co substrate - temporary association such as NAD+
Prosthetic - permanent association Heme

13

Ideal temp for enzyme activity

37 degrees C

14

Ideal pH for enzyme activity

4-8 with the exception of pepsin

15

Gastric proton pumps are on what type of cell

Parietal cells

16

What variable stands for enzyme - substrate affinity?

Km

17

/What shape is a Michaelis menten plot?

Hyperbolic

18

/What shape is a lineweaver Burke plot?

Linear

19

Competitive inhibitor

Resemble substrate - compete for the active site on an enzyme
No effect on vmax - increase Km

20

1/2 vmax

Km

21

Lineweaver Burke x intercept

-1/Km

22

Y intercept lineweaver Burke

1/Vmax

23

Slope lineweaver Burke plot

Km/Vmax

24

Non competitive inhibitor

Bind to E or ES complex not at the active site
Decreases Vmax
Unchanged Km
Effect cannot be altered by increasing substrate concentration

25

Uncompetitive inhibition

Decrease in vmax and Km by the same factor - lineweaver Burke plot with and without inhibitor yields parallel lines

26

How can you inhibit metaloenzymes

Use metal cofactor - chelating the cofactor will inhibit enzyme activity

This can be used to stop lead poisoning through using edta which is a lead chelator (lead normally will bind heme rendering it useless)

27

Enzyme inactivation
VMax? Up or down
Km? Up or down
Reversible or not?
Similar lineweaver Burke plot to what type on inhibition?

Vmax decreased
Unchanged Km
Irreversible
Non competitive is similar but is reversible

28

Allosteric enzymes
Type of bond ?
Location of bond?
Positive or negative effect?

Noncovalent bond
Not at the catalytic site
Induce conformational change to create a positive or negative impact
Utilize feedback inhibition where product of enzyme is a negative effector

29

What shape plot does a allosteric enzyme create

Sigmoidal

30

What is an Isozyme?

Same catalytic function, different primary sequence. Different binding sites. Can be used as marker for myocardial infarction - creatine kinase, aspartate, aminotransferase and more. Different isozymes can be used based on time after myocardial event.