Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Principles Biochemistry > Lecture 6 Enzymes > Flashcards

Lecture 6 Enzymes Flashcards

1
Q

What Are enzymes

A

Biological catalysts speeds up chemical reactions or the rate at which equilibrium is reached

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the special features of enzymes

A
  • There Catalysts
  • Effecient - Can increase rate of rection by factor of
  • 1020
  • Specific - have limited range of substrates and some can distinguish Steroisomers
  • Potent - Can covert many substrate molecules into products in seconds
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is Activation Energy

A
  • The energy needed to put atoms/molecules in a position where they are unstable and ready to break
  • This is know as the Transition state
  • Once achieved the rest of the reaction is automatic
  • No-futher energy is needed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How do enzymes speed up chemical reactions

A
  • They lower the activation energy (hence less energy is needed to put atoms in the unstable stage)
  • Enzymes make it easier to reach the transition state
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the transtion state

A
  • Reaction intermediate species which has the greatest free energy
  • Enzymes reduce the activation energy by providing an alternative reaction pathway
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the Glycogen Storage Disease

A
  • Enzyme dificiency that results in failure of glycogen to enter transition state/Phophorylated state
  • Cannot get Glucose production from glycogen
  • Defective glyogen synthesis in muscle,liver and kidney
  • 11 varient defects in 12 glycogen or glucose metabolising enzymes
  • Von gierkes diease - most common
  • Glucose 6 phosphotase deficiency
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the symptoms of von gierkes disease

A
  • Hypoglycaemia
  • Hepatomygly
  • Skin and mouth ulcers
  • Bacterial and fungal infeciton
  • Bowel inflammation and irritability
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the Treatment for von gierkes disease

A
  • Slow release glucose meal - Corn-starch
  • Feed little and often - Mimics glycogen conversion to glucose
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are Co-factors and Co-enzymes

A

Assist enzymes in their catalysing acitivity

  • Co-factor - Metal ions, inorganic
  • Co-enzymes - Organic molecules
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How do Co-factors associate with enzmyes

A
  • Form co-ordination centre in enzyme
  • enzymes becomes Metalloprotein
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

how do co-enzymes associate with enzymes

A
  • Temporarily associate with enzymes
  • They can change charge or structure during the course of the reaciton but are regenerated
  • Tightly bound co-enzymes are prothetic groups
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what are Prothetic groups

A

When a co-enzyme bind tightly to an enzyme

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what are apoenzymes

A

Enzymes without a co-factor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are holoenzymes

A

Enzymes with co-factors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Give examples of co-factors

A
  • Zing, iron, copper
  • Involved in Redox reactions
  • Stabalise transition state
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Give examples of Co-enzymes

A
  • Derivatives of vitamines
  • NAD+ and FAD - Redox reactions
  • Group transfer processses
  • Co-enzmye A- transfers acteyl groups
  • ATP- Transfers Phosphate groups
17
Q

Specific example of a Co-enzmye

A
  • Vitamines
  • Symptoms of vitamine deficiencies reflect the loss of specific enzyme activities
  • Deficiencies may be dietary or functional
18
Q

What is a common co-enzyme for redox reactions

A
  • NAD+
  • NAD+ <–> NADH
  • Easily regenerated
  • May donate or recieve electrones during catalysis
19
Q

What are 2 features of enzyme-substrate binding

A
  • Lock and key model- Active is complementory to substrate shape
  • Induced fit model- Binding induced a confromation change in enzyme = Complementory fit

Example: Hixokinase upon binding glucose

20
Q

What are Serine Proteases

A
  • Enzymes
  • Cleave peptide bonds at specific sites
  • 3 Types
  • Contain reactive serine residues
21
Q

What is Chymotripsin active site

A
  • Hydrophobic pocket which binds
  • aromatic amino acids
22
Q

What is the Trypsin active site

A
  • Negatively charged ASP (asparic acid) Interacts with postively charged Lys or Arg
23
Q

What is the Elastase active site cleavage

A
  • Partially blocked
  • Only amino acid will small or no side chains can binds
  • small hydrophic pocket - hydrophobic amino acids
24
Q

What are isoenzymes

A
  • Isforms of enzymes
  • Catalyse the same reaction but have different properties and structure
25
Q

Where are isoemzymes found

A
  • Synthesised at different faetal and embryonic development
  • Present in different tissues
  • Present in different cellular locations
26
Q

Give an example for an Isoenzyme

A

Lactate Dehydrogenase

27
Q

What are the two Subunits of Lactate Dehydrogenase

A
  • H(heart) - promotes aerobic metabolism
  • M(Mucle)- Promotes anaerobic metabolism

Under normal O2 you get translation of the H form subunit

Under low O2 stress you get the M form

these sub-units then come together to form the enzyme which can have a mix of the sub-units or just 1 fromv

28
Q

which which disease will you get increased formation of lactate dehydrogenase M subunit

A
  • Heart disease
  • Stroke
  • Cancer

Anything that can cause hypoxia

29
Q

What is the significance of the isoenzyme Creatine Kinase

A
  • Can be used to diagnose Heart attack or stroke
  • B form appearance in blood = Stroke
  • MB from appearance in blood = MI
30
Q

How are enzymes regulated by Reversible covalent modification

A

phosphrylation/Dephosphorylation

  • Can activate and inactivate enzymes
  • Example: Glycogen phosphatase - Converted from inactive (a) to active (b)
31
Q

What do kinases and phosphotases do

A
  • Kinase = phosphorylation
  • Phosphotase = Dephosphorylation
32
Q

How are enzymes regulated by irriversible covalent modification

A
  • Zymogens - inactive precursors of an enzyme
  • Irreversible transformed into an active enzyme but cleavage of a covalent bond
33
Q

what are zymogens

A

Inactive precursors of enzymes

34
Q

Given an example of irreversible covalent modification of an enzyme

A
  • in pancreas: trypsinogen and chymotrypsinogen, inactive precursors, are formed
  • in small intestine: enteropeptidase cleaves trypsinogen to form active trypsin which cleaves chymotrypsinogen to form active chymotrypsin
35
Q

What is irreversible proteolytic modification

A

Some enzymes are regulated by partial proteolysis

36
Q

Answer these Questions

A

Principles Biochemistry (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions